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Page 1: Chemistry Past Papers

56/3 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸ü ÃÖ Ö µÖ ®Ö × ¾Ö – Ö Ö ®Ö (ÃÖî ü Ö × ®ŸÖ Û ú ) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ŸÖÛú ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛúŸÖÖ ÆüÖê, ŸÖÖê »ÖÖòÝÖ ™êü²Ö»ÖÖë ÛúÖ ¯ÖϵÖÖêÝÖ Ûú¸ëü … Ûîú»ÖÛãú»Öê™ü¸üÖë Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/C 56/3

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 12 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

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• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 3

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General Instructions :

(i) All questions are compulsory.

(ii) Question number 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Question number 6 to 10 are short answer questions and carry 2 marks each.

(iv) Question number 11 to 22 are also short answer questions and carry 3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Question number 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. ‘Ûúß»Öê™’ü ¯ÖϳÖÖ¾Ö ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

What is meant by chelate effect ?

2. ×®Ö´®Ö ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

CH3 – CH2 – CHO

Write the IUPAC name of the following :

CH3 – CH2 – CHO

3. ×®Ö´®Ö ÛúÖê õÖÖ¸üßµÖ õÖ´ÖŸÖÖ Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ¾µÖ¾Ö×Ã£ÖŸÖ Ûúßו֋ :

‹ê×®Ö»Öß®Ö, p-®ÖÖ‡™ÒüÖê‹ê×®Ö»Öß®Ö †Öî ü p-™üÖ»Ö㇛Ìüß®Ö

Arrange the following in increasing order of basic strength :

Aniline, p-Nitroaniline and p-Toluidine

4. AgCl ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ Ã™üÖê‡×ÛúµÖÖê Öß™Òüß ¤üÖêÂÖ ¤ü¿ÖÖÔŸÖÖ Æîü ?

What type of stoichiometric defect is shown by AgCl ?

5. ‡´Ö»¿Ö®Ö ŒµÖÖ ÆüÖêŸÖê Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

What are emulsions ? Give an example.

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6. ¯ÖÖê™îü×¿ÖµÖ´Ö ¯Ö¸ü´ÖïÝÖ®Öê™ü Ûúß ×®Ö´ÖÖÔÞÖ ×¾Ö×¬Ö ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ … †´»ÖßÛéúŸÖ ¯Ö¸ü´ÖîÓÝÖ®Öê™ü †ÖòŒÃÖî×»ÖÛú †´»Ö Ûêú ÃÖÖ£Ö ÛîúÃÖê

†×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ? †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ …

†£Ö¾ÖÖ

¯ÖÖê™îü×¿ÖµÖ´Ö ›üÖ‡ÛÎúÖê Öê™ü Ûúß †ÖòŒÃÖßÛú¸üÞÖ ×ÛÎúµÖÖ ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ †Öî ü ‡ÃÖÛúß (i) †ÖµÖÖê›üÖ‡›ü (ii) H2S Ûêú ÃÖÖ£Ö

ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ×»Ö×ÜÖ‹ …

Describe the preparation of potassium permanganate. How does the acidified

permanganate solution react with oxalic acid ? Write the ionic equations for the

reactions.

OR

Describe the oxidising action of potassium dichromate and write the ionic equations

for its reaction with (i) an iodide (ii) H2S.

7. ‹£Ö®ÖÖò»Ö ÃÖê ‹£Öß®Ö ²Ö®Ö®Öê ´Öë †´»Ö ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ×ÛÎúµÖÖ×¾Ö×¬Ö ×»Ö×ÜÖ‹ …

Write the mechanism of acid dehydration of ethanol to yield ethene.

8. ×®Ö´®Ö ¯Ö¤üÖë Ûúß ¯Ö׸ü³ÖÖÂÖÖ‹Ñ ×»Ö×ÜÖµÖê :

(i) ´ÖÖê»ÖÖÓ¿Ö (x)

(ii) ‹Ûú ×¾Ö»ÖµÖ®Ö Ûúß ´ÖÖê»Ö»ÖŸÖÖ (m)

Define the following terms :

(i) Mole fraction (x)

(ii) Molality of a solution (m)

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9. •Ö߸üÖê †Öò›Ôü¸ü †Öî ü ׫üŸÖßµÖ †Öò›Ôü¸ü †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛúÖë Ûêú µÖæ×®Ö™ü ×»Ö×ÜÖ‹ ˆÃÖ ×ãÖ×ŸÖ ´Öë •Ö²Ö ÃÖÖÓ¦üŸÖÖ

ÛúÖê mol L–1 †Öî ü ÃÖ´ÖµÖ ÛúÖê ÃÖêÛúÞ›üÖë ´Öë ×»ÖÜÖÖ ÝÖµÖÖ ÆüÖê …

Write units of rate constants for zero order and for the second order reactions if the

concentration is expressed in mol L–1 and time in second.

10. ×®Ö´®Ö Ûú£Ö®ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ±úÖòñúÖê üÃÖ Ûúß †¯ÖêõÖÖ ®ÖÖ‡™ÒüÖê•Ö®Ö ²ÖÆãüŸÖ Ûú´Ö ÃÖ×ÛÎúµÖ Æîü …

(ii) NF3 ‹Ûú ‰ú´ÖÖõÖê Öß ¯Ö¤üÖ£ÖÔ Æîü ¯Ö¸ü®ŸÖã NCl3 ‰ú´ÖÖ¿ÖÖêÂÖß ¯Ö¤üÖ£ÖÔ Æîü …

Explain the following :

(i) Nitrogen is much less reactive than phosphorus.

(ii) NF3 is an exothermic compound but NCl3 is an endothermic compound.

11. ‘†®ÖÖ®Öã ÖÖŸÖ®Ö’ ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ‹Ûú ˆ¤üÖÆü üÞÖ ¤üßו֋ …

What is meant by ‘disproportionation’ ? Give one example of disproportionation

reaction in aqueous solutions.

12. ×®Ö´®Ö×»Ö×ÜÖŸÖ Ûêú IUPAC ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

Write the IUPAC name of the following :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

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13. ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ¤üßו֋ :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

Give the IUPAC names of the following compounds :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

14. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ²Öê×®•Ö»Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ²Öê×®•Ö»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë

(ii) ‹×£Ö»Ö ´ÖîÝ®Öß×¿ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ¯ÖÏÖê Öê®Ö-1-†Öò»Ö ´Öë

(iii) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë

How are the following conversions carried out ?

(i) Benzyl chloride to Benzyl alcohol

(ii) Ethyl magnesium chloride to Propan-1-ol

(iii) Propene to Propan-2-ol

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15. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ×»Ö×ÜÖ‹ :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

Write the major product in the following equations :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

16. ¯ÖÏÖê™üß®Ö ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ×®Ö´®Ö ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¯Öê ™üÖ‡›ü Ø»ÖÛêú•Ö

(ii) ¯ÖÏÖ‡´Ö¸üß ÃÖÓ ü“Ö®ÖÖ

(iii) ›üß®Öî“Öã êü¿Ö®Ö

Define the following as related to proteins :

(i) Peptide linkage

(ii) Primary structure

(iii) Denaturation

17. ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ ¯Ö¤ü Ûúß ¾µÖÖܵÖÖ Ûúßו֋ †Öî ü ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ Ûêú ¤üÖê ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

Explain the term ‘copolymerization’ and give two examples of copolymerization.

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18. ×ÃÖ»¾Ö¸ü fcc •ÖÖ»ÖÛú ´Öë ×ÛÎúÙü×»ÖŸÖ ÆüÖêŸÖÖ Æîü … µÖפü µÖæ×®Ö™ü ÃÖê»Ö Ûêú ÛúÖê ü Ûúß »Ö´²ÖÖ‡Ô 4.077 × 10–8 cm ÆüÖê, ŸÖÖê

×ÃÖ»¾Ö¸ü ÛúÖ †¬ÖÔ¾µÖÖÃÖ (r) ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

Silver crystallises in fcc lattice. If edge length of the unit cell is 4.077 × 10–8 cm, then

calculate the radius of silver atom.

19. Ûêú®Ö-¿ÖãÝÖ¸ü (M.W. 342) ÛúÖ 5 ¯ÖÏ×ŸÖ¿ÖŸÖ ‘ÖÖê»Ö (¦ü¾µÖ´ÖÖ®Ö †Ö¬ÖÖ¸ü ¯Ö¸ü) ‹Ûú ¯Ö¤üÖ£ÖÔ X Ûêú 0.877% ‘ÖÖê»Ö Ûêú ÃÖÖ£Ö

†Ö‡ÃÖÖê™üÖê×®ÖÛú Æîü … X ÛúÖ †ÖÞÖ×¾ÖÛú ³ÖÖ¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

A 5 percent solution (by mass) of cane-sugar (M.W. 342) is isotonic with 0.877%

solution of substance X. Find the molecular weight of X.

20. ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛú 60 s–1 Æîü … †×³ÖÛúÖ¸üÛú Ûêú ¯ÖÏÖ¸ü×´³ÖÛú ÃÖÖÓ¦üÞÖ ÛúÖê ‡ÃÖÛêú 1/10

ŸÖÛú ‘Ö™®Öêê ´Öë ×ÛúŸÖ®ÖÖ ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ?

The rate constant for a first order reaction is 60 s–1. How much time will it take to

reduce the initial concentration of the reactant to its 1/10th

value ?

21. ×®Ö´®Ö ¯ÖÏÛÎú´ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ›üÖµÖ×»Ö×ÃÖÃÖ

(ii) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(iii) ×™üÞ›ü»Ö ¯ÖϳÖÖ¾Ö

Describe the following processes :

(i) Dialysis

(ii) Electrophoresis

(iii) Tyndall effect

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22. ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ‹ê»Öã×´Ö×®ÖµÖ´Ö Ûêú ¬ÖÖŸÖãÛú´ÖÔ ´Öë ÛÎúÖ‡µÖÖê»ÖÖ‡™ü Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(ii) ³Ö•ÖÔ®Ö ×ÛÎúµÖÖ †Öî ü ×®ÖßÖÖ¯Ö®Ö ´Öë †ÓŸÖ¸ü Ûúßו֋ …

(iii) ‘ÛÎúÖê Öîê™üÖêÝÖÏî±úß’ ¯Ö¤ü ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

†£Ö¾ÖÖ

»ÖÖêÆüÖ ²Ö®ÖÖ®Öê Ûêú ×»Ö‹ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë ´Öë ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ‹Ñ ×»Ö×ÜÖ‹ …

Answer the following :

(i) What is the role of cryolite in the metallurgy of aluminium ?

(ii) Differentiate between roasting and calcination.

(iii) What is meant by the term ‘chromatography’ ?

OR

Write the reactions taking place in different zones of the blast furnace to obtain Iron.

23. ®Ö߸ü•Ö ×›ü ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ‘Ö¸ü Ûêú ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®Öê Ûêú ×»ÖµÖê ÝÖµÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ¾ÖÆü Ûãú”û ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ

¤êüÜÖÖ … ¾ÖÆü Ûãú”û ‹êÃÖß ×™ü×ÛúµÖÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß, ŒµÖÖë×Ûú ˆÃÖÛêú

¤üÖ¤üÖ ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ¾ÖÆüÖÑ ŸÖß®Ö ¯ÖÏÛúÖ¸ü Ûúß ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ £ÖßÓ … ˆÃÖ®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ¾ÖÆü ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤêü

•ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ¸ü×ÆüŸÖ ÛúÖ ®ÖÖ´Ö ¤üßו֋ •ÖÖê ®Ö߸ü•Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ŒµÖÖ ›üÖŒ™ü¸ü Ûêú ¯Ö“Öá Ûêú ײ֮ÖÖ ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ®Ö߸ü•Ö Ûêú ×»ÖµÖê ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ÃÖê ®Ö߸ü•Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖÏןֻÖ×õÖŸÖ ÆüÖêŸÖÖ Æîü ?

Neeraj went to the departmental store to purchase groceries. On one of the shelves he

noticed sugar free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar free tablets. He decided to buy sucrolose

which was good for his grandfather’s health.

(i) Name another sugar free tablet which Neeraj did not purchase.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Neeraj is reflected above ?

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24. (a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) p-´Öê×£Ö»Ö²Öï•Ö̋׻›üÆüÖ‡›ü

(ii) 4-´Öê×£Ö»Ö¯Öî®™ü-3-‡Ô®Ö-2-†Öò®Ö

(b) ×®Ö´®Ö µÖÖî×ÝÖÛú µÖãÝ´ÖÖë ´Öë †ÓŸÖ¸ü Ûú¸ü®Öê Ûêú ×»ÖµÖê ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“ÖÖë ÛúÖê ¤üßו֋ :

(i) ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü †Öî ü ‹×£Ö»Ö²ÖꮕÖÌÖê‹™ü …

(ii) ²ÖꮕÖî×»›üÆüÖ‡›ü †Öî ü ‹êÃÖß™üÖê±úß®ÖÖê®Ö

(iii) ±úß®ÖÖò»Ö †Öî ü ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü

†£Ö¾ÖÖ

(a) ×®Ö´®Ö ¾µÖ㟯֮®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö¸êü×ÜÖŸÖ Ûúßו֋ :

(i) ¯ÖÏÖê Öê®ÖÖê®Ö †Öò׌ÃÖ´Ö

(ii) CH3CHO ÛúÖ ÃÖê ÖßÛúÖ²Öì•ÖÖê®Ö

(b) ‹£Öî®ÖÖò»Ö ÛúÖê †Ö¯Ö ×®Ö´®Ö µÖÖî×ÝÖÛúÖë ´Öë ÛîúÃÖê ºþ¯ÖÖÓŸÖ׸üŸÖ Ûú ëüÝÖê ? ÃÖ´Ö²Ö¨ü ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤üßו֋ …

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

(a) Draw the structures of the following :

(i) p-Methylbenzaldehyde

(ii) 4-Methylpent-3-en-2-one

(b) Give chemical tests to distinguish between the following pairs of compounds :

(i) Benzoic acid and Ethyl benzoate.

(ii) Benzaldehyde and Acetophenone.

(iii) Phenol and Benzoic acid.

OR

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(a) Draw the structures of the following derivatives :

(i) Propanone oxime

(ii) Semicarbazone of CH3CHO

(b) How will you convert ethanal into the following compounds ? Give the chemical

equations involved.

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

25. (a) ÝÖÏã Ö 16 Ûêú ŸÖ¢¾Ö ÃÖÖ¬ÖÖ¸üÞÖŸÖµÖÖ ¯ÖÏ£Ö´Ö †ÖµÖ®Ö®Ö ‹®£ÖÖß ŸÖŸÃÖ´²Ö®¬Öß †Ö¾ÖŸÖÔ ¾ÖÖ»Öê ÝÖÏã Ö 15 Ûêú ŸÖ¢¾ÖÖë Ûúß

ŸÖã»Ö®ÖÖ ´Öë Ûú´Ö ´ÖÖ®Ö ¤ü¿ÖÖÔŸÖê Æïü … ‹êÃÖÖ ŒµÖÖë Æîü ?

(b) ŒµÖÖ ÆüÖêŸÖÖ Æîü •Ö²Ö –

(i) ÃÖÖÓ¦ü H2SO4 ÛúÖê CaF2 ¯Ö¸ü ›üÖ»ÖÖ •ÖÖŸÖÖ Æîü ?

(ii) ÃÖ»±Ìú¸ü ›üÖ‡†ÖòŒÃÖÖ‡›ü “ÖÖ¸üÛúÖê»Ö Ûúß ˆ¯Ö×ãÖ×ŸÖ ´Öë Œ»ÖÖê üß®Ö ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü ?

(iii) †´ÖÖê×®ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖê Ca(OH)2 Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ×ÛúµÖÖ •ÖÖŸÖÖ Æîü ?

†£Ö¾ÖÖ

(a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) BrF3

(ii) XeO3

(b) ×®Ö´®Ö ¯ÖÏ¿®ÖÖë Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) PH3Ûúß †¯ÖêõÖÖ NH3 ŒµÖÖë †×¬ÖÛú õÖÖ¸üßµÖ ÆüÖêŸÖÖ Æîü ?

(ii) Æîü»ÖÖê•Ö®Ö ¯ÖÏ²Ö»Ö †ÖòŒÃÖßÛúÖ¸üÛú ŒµÖÖë ÆüÖêŸÖê Æïü ?

(iii) XeOF4 Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

Page 11: Chemistry Past Papers

56/3 11 [P.T.O.

(a) Elements of Gr. 16 generally show lower value of first ionization enthalpy

compared to the corresponding periods of Gr. 15. Why ?

(b) What happens when

(i) concentrated H2SO4 is added to CaF2 ?

(ii) sulphur dioxide reacts with chlorine in the presence of charcoal ?

(iii) ammonium chloride is treated with Ca(OH)2 ?

OR

(a) Draw the structure of the following :

(i) BrF3

(ii) XeO3

(b) Answer the following :

(i) Why is NH3 more basic than PH3 ?

(ii) Why are halogens strong oxidising agents ?

(iii) Draw the structure of XeOF4.

26. ∆rG° †Öî ü e.m.f.(E) ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ •ÖÖê 25 °C ¯Ö¸ü Ùïü›ü›Ôü ×ãÖ×ŸÖ ´Öë ×®Ö´®Ö ÃÖê»Ö ÃÖê ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

פüµÖÖ ÝÖµÖÖ : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

†Öî ü F = 96500 C mol–1

†£Ö¾ÖÖ

(a) ‹Ûú ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûêú ×¾Ö»ÖµÖ®Ö Ûêú ×»ÖµÖê “ÖÖ»ÖÛúŸÖÖ †Öî ü ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

ÃÖÖÓ¦üŸÖÖ Ûêú ÃÖÖ£Ö ˆ®ÖÛêú ¯Ö׸ü¾ÖŸÖÔ®Ö Ûúß ¾µÖÖܵÖÖ Ûúßו֋ …

Page 12: Chemistry Past Papers

56/3 12

(b) ˆÃÖ ÝÖî»Ö¾ÖÖò×®ÖÛú ÃÖê»Ö Ûêú Ùïü›ü›Ôü ÃÖê»Ö ×¾Ö³Ö¾Ö ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ וÖÃÖ´Öë ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÆüÖêŸÖß Æîü :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

†×³Ö×ÛÎúµÖÖ ÛúÖ ∆rG° †Öî ü ŸÖ㻵ÖÖÓÛúß ×ãָüÖÓÛú ÛúÖ ¯Ö׸üÛú»Ö®Ö ³Öß Ûúßו֋ …

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

Calculate ∆rG° and e.m.f. (E) that can be obtained from the following cell under the

standard conditions at 25 °C :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

Given : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

and F = 96500 C mol–1.

OR

(a) Define conductivity and molar conductivity for the solution of an electrolyte.

Discuss their variation with concentration.

(b) Calculate the standard cell potential of the galvanic cell in which the following

reaction takes place :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

Calculate the ∆rG° and equilibrium constant of the reaction also.

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

____________

Page 13: Chemistry Past Papers

1

Qu

es. Value points Marks

1 Formation of stable complex by polydentate ligand. 1

2 Propanal 1

3 p-Nitroaniline < Aniline < p-Toluidine 1

4 Frenkel defect 1

5 Emulsions are liquid – liquid colloidal systems.

For example – milk, cream (or any other one correct example)

½ + ½

6 Potassium permanganate is prepared by fusion of MnO2 with an alkali metal hydroxide and an

oxidising agent like KNO3. This produces the dark green K2MnO4 which disproportionates in a

neutral or acidic solution to give permanganate.

Oxalate ion or oxalic acid is oxidised at 333 K:

OR

1

1

6 i)

ii)

1

1

7

½

½

1

CHEMISTRY MARKING SCHEME

SET -56/3

Compt. July, 2015

Page 14: Chemistry Past Papers

2

8 i)

ii) Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the

solvent. Or

1

1

9 Zero order : mol L-1

s-1

Second order : L mol-1

s-1

1

1

10 i) Due to high bond dissociation enthalpy of N N

ii) Due to low bond dissociation enthalpy of F2 than Cl2 and strong bond formation

between N and F

1

1

11 Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

1 ½

1 ½

12 i) Hexaamminecobalt(III) chloride

ii) Tetrachlorido nickelate(II)

iii) Potassium hexacyanoferrate(III)

1

1

1

13 i) 2-bromobutane

ii) 1, 3-dibromobenzene

iii) 3-choloropropene

1

1

1

14

i)

ii)

1

1

1

15

i)

1

Page 15: Chemistry Past Papers

3

ii)

iii)

1

1

16 i) Peptide linkage – in proteins, -amino acids are connected to each other by peptide

bond or peptide linkage (-CONH- bond).

ii) Primary structure - each polypeptide in a protein molecule having amino acids which

are linked with each other in a specific sequence.

iii) Denaturation - When a protein is subjected to physical change like change in

temperature or chemical change like change in pH, protein loses its biological activity.

1

1

1

17 Copolymerisation is a polymerisation reaction in which a mixture of more than one monomeric

species is allowed to polymerise and form a copolymer.

(or any other correct example)

1

1

1

18 r =

r=

r = 1.44 x cm

1

1

1

cane sugar = πXח 19

Therefore, ccane sugar = cX (where c is molar concentration)

=

=

MX =

gmol

-1

MX = 59.9 or 60 gmol-1

1

1

1

20 k=

log

1

Page 16: Chemistry Past Papers

4

60 s-1

=

log

t=

log 10

t=

s

t= 0.0384 s

1

1 21 i) It is a process of removing the dissolved substance from a colloidal solution by means

of diffusion through a semi - permeable membrane.

ii) The movement of colloidal particles under an applied electric potential towards

oppositely charged electrode is called electrophoresis.

iii) Colloidal particles scatter light in all directions in space. This scattering of light

illuminates the path of beam in the colloidal dispersion.

1

1

1 22 i) It lowers the melting point of alumina / acts as a solvent.

ii)

Roasting Calcination

Ore is heated in a regular supply of air Heating in a limited supply or

absence of air.

(Or with equation)

iii) It is a process of separation of different components of a mixture which are differently

adsorbed on a suitable adsorbent. OR

1

1

1

22

(any 6 correct equations)

6 x ½

= 3

23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2 24 a) i)

ii)

b) i)Add NaHCO3, benzoic acid will give brisk effervescence of CO2 whereas ethylbenzoate

1

1

Page 17: Chemistry Past Papers

5

will not.

ii)Add NaOH and I2, acetophonone forms yellow ppt of iodoform on heating whereas

benzaldehyde will not.

iii)Add neutral FeCl3, phenol gives violet colouration whereas benzoic acid does not. (or any other correct test)

OR

1

1

1

24 a) i)

ii)

b) i)

ii)

iii)

1

1

1

1

1

25 a) Due to relatively stable half – filled p-orbitals of group 15 elements

b) i) CaF2 + H2SO4 CaSO4 + 2HF

ii)

iii)

OR

2

1

1

1

25

a) i)

1

Page 18: Chemistry Past Papers

6

ii)

b) i)Due to small size of nitrogen, the lone pair of electron on nitrogen is localized/ easily

available for donation.

ii)Because they need only one electron to attain stable/noble gas configuration.

iii)

1

1

1

1

26 E0cell = E

0Sn2+ / Sn - E

0Zn2+ / Zn

= - 0.14V –(- 0.76V)

= 0.62V

∆rG0 = -n F E

0cell

= - 2 x 96500 C mol-1

x 0.62 V

= - 119660 J mol-1

Ecell = E0

cell -

log

Ecell = 0.62 -

log

OR

1

1

1

1

1

26 a) The conductivity of a solution at any given concentration is the conductance of one unit

volume of solution kept between two platinum electrodes with unit area of cross section

and at a distance of unit length.

Molar conductivity of a solution at a given concentration is the conductance of the volume

V of solution containing one mole of electrolyte kept between two electrodes with area of

cross section A and distance of unit length.

Molar conductivity increases with decrease in concentration.

b)E0cell = E

0C - E

0A

= 0.80V – 0.77V

= 0.03V

∆rG0 = -n F E

0cell

= - 1 x 96500 C mol-1

x 0.03 V

= - 2895 J mol-1

Log Kc=

½

½

1

½

½

1

½

Page 19: Chemistry Past Papers

7

Dr. Sangeeta Bhatia Sh. S.K. Munjal Sh. D.A. Mishra

Ms. Garima Bhutani

Log Kc=

Log Kc= 0.508

½

Page 20: Chemistry Past Papers

56/1/3 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸ü ÃÖ Ö µÖ ®Ö × ¾Ö – Ö Ö ®Ö (ÃÖî ü Ö × ®ŸÖ Û ú ) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú »ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1/C 56/1/3

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 11 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 11 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 3

Page 21: Chemistry Past Papers

56/1/3 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. No. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. No. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. No. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. No. 23 is a value based question and carry 4 marks.

(vi) Q. No. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculator is not allowed.

1. ÛúÖò ¯»ÖêŒÃÖ [Ni(NH3)6]Cl2 ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ …

What is the IUPAC name of the complex [Ni(NH3)6]Cl2 ?

2. ×®Ö´®Ö µÖÖî×ÝÖÛú Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

3-´Öê×£Ö»Ö¯Öê®™îü®Öî»Ö

Draw the structure of 3-methylpentanal.

3. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

Complete the following reaction equation :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

4. ‹Ûú †ÓŸÖ: Ûêú×®¦üŸÖ ‘Ö®ÖßµÖ ÃÖÓ ü“Ö®ÖÖ ´Öë ¯Ö¸ü´ÖÖÞÖã†Öë Ûúß ÃÖÓܵÖÖ ¯ÖÏ×ŸÖ ‹ÛúÛú ÛúÖêךüÛúÖ (z) ŒµÖÖ ÆüÖêŸÖß Æîü ?

What is the no. of atoms per unit cell (z) in a body-centred cubic structure ?

5. ÃÖŸÖÆü ¸üÃÖÖµÖ®Ö Ûêú ÃÖÓ¤ü³ÖÔ ´Öë ›üÖµÖÖ×»Ö×ÃÖÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

In reference to surface chemistry, define dialysis.

Page 22: Chemistry Past Papers

56/1/3 3 [P.T.O.

6. ‹£Öî®ÖÖò»Ö Ûêú ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ¯ÖÏ×ÛÎúµÖÖ Ûêú “Ö¸üÞÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

Explain the mechanism of dehydration steps of ethanol :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

7. ×¾Ö»ÖµÖ®Ö Ûêú ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛúÖê ¯Ö× ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾Ö»ÖµÖ®Ö ´Öë ×¾Ö»ÖêµÖ Ûêú ÃÖÖÓ¦üÞÖ ÃÖê ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛîúÃÖê ÃÖÓ²Ö×®¬ÖŸÖ Æîü ?

Define osmotic pressure of a solution. How is the osmotic pressure related to the

concentration of a solute in a solution ?

8. ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) †×³Ö×ÛÎúµÖÖ Ûúß †¬ÖÖÔµÖã (t½)

(ii) ¾ÖêÝÖ ×ãָüÖÓÛú (k)

Define the following terms :

(i) Half-life of a reaction (t½)

(ii) Rate constant (k)

9. ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) H2SO4

(ii) XeF2

Draw the structures of the following :

(i) H2SO4

(ii) XeF2

10. ‘†ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö’ ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ ÛúÖ ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

†£Ö¾ÖÖ

ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã ¸üÃÖÖµÖ®Ö Ûêú ×®Ö´®Ö »ÖõÖÞÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ÃÖã—ÖÖ‡‹ :

(i) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ †Öî ü ˆ®ÖÛêú µÖÖî×ÝÖÛú ÃÖÖ´ÖÖ®µÖŸÖÖ †®Öã“Öã ²ÖÛúßµÖ ÆüÖêŸÖê Æïü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¯Ö׸ü¾ÖŸÖÔ®Ö¿Öᯙ ˆ¯Ö“ÖµÖ®Ö †¾ÖãÖÖ‹Ñ ¯ÖϤüÙ¿ÖŸÖ Ûú¸üŸÖß Æïü …

What is meant by ‘disproportionation’ ? Give an example of a disproportionation

reaction in aqueous solution.

OR

Suggest reasons for the following features of transition metal chemistry :

(i) The transition metals and their compounds are usually paramagnetic.

(ii) The transition metals exhibit variable oxidation states.

Page 23: Chemistry Past Papers

56/1/3 4

11. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë …

(ii) ²Öê×®•ÖÌ»Ö Œ»ÖÖê üÖ‡›ü ÛúÖê ²Öê×®•ÖÌ»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë …

(iii) ‹ê×®ÖÃÖÖê»Ö ÛúÖê p-²ÖÎÖê ÖÖê‹ê×®ÖÃÖÖê»Ö ´Öë …

How are the following conversions carried out ?

(i) Propene to propane-2-ol

(ii) Benzyl chloride to Benzyl alcohol

(iii) Anisole to p-Bromoanisole

12. ‹Ûú ‹ê üÖê Öî×™üÛú µÖÖî×ÝÖÛú ‘A’ •Ö»ÖßµÖ †´ÖÖê×®ÖµÖÖ Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ÆüÖê®Öê †Öî ü ÝÖ´ÖÔ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘B’ ²Ö®ÖÖŸÖÖ Æîü

•ÖÖê Br2 †Öî ü KOH Ûêú ÃÖÖ£Ö ŸÖÖ×¯ÖŸÖ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘C’ ²Ö®ÖÖŸÖÖ Æîü … ‘C’ ÛúÖ †ÖÞÖ×¾ÖÛú ÃÖæ¡Ö C6H7N Æîü …

A, B †Öî ü C µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ

Ûúßו֋ …

An aromatic compound ‘A’ on treatment with aqueous ammonia and heating forms

compound ‘B’ which on heating with Br2 and KOH forms a compound ‘C’ of

molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B

and C.

13. ×¾Ö™üÖ×´Ö®Öë ÛîúÃÖê ¾ÖÝÖáÛéúŸÖ Ûúß •ÖÖŸÖß Æïü ? ¸üŒŸÖ Ûêú ÃÛÓú¤ü®Ö Ûêú •ÖÖê ×¾Ö™üÖ×´Ö®Ö ˆ¢Ö¸ü¤üÖµÖß ÆüÖêŸÖê Æïü ˆ®ÖÛêú ®ÖÖ´Ö ¤üßו֋ …

How are vitamins classified ? Name the vitamin responsible for the coagulation of

blood.

14. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) ²Öæ®ÖÖ-S

(ii) ®Ö߆Öê ÖÏß®Ö

(iii) ™êü°»ÖÖò®Ö

Write the names and structures of the monomers of the following polymers :

(i) Buna-S

(ii) Neoprene

(iii) Teflon

Page 24: Chemistry Past Papers

56/1/3 5 [P.T.O.

15. ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¿ÖÖò™üÛúß ¤üÖêÂÖ

(ii) ±ÏëúÛêú»Ö ¤üÖêÂÖ

(iii) F-Ûëú¦ü

Define the following :

(i) Schottky defect

(ii) Frenkel defect

(iii) F-centre

16. ‹×£Ö»Öß®Ö Ý»ÖÖ‡ÛúÖê»Ö (C2H4O2) ÛúÖ 45 g •Ö»Ö Ûêú 600 g Ûêú ÃÖÖ£Ö ×´Ö»ÖÖµÖÖ ÝÖµÖÖ Æîü … ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(i) ×Æü´ÖÖÓÛú ÛúÖ †¾Ö®Ö´Ö®Ö †Öî ü

(ii) ×¾Ö»ÖµÖ®Ö ÛúÖ ×Æü´ÖÖÓÛú

(פüµÖÖ ÝÖµÖÖ Æîü : Kf ÛúÖ ´ÖÖ®Ö ¯ÖÖ®Öß Ûêú ×»Ö‹ = 1.86 K kg mol–1)

45 g of ethylene glycol (C2H4O2) is mixed with 600 g of water. Calculate

(i) the freezing point depression and

(ii) the freezing point of the solution

(Given : Kf of water = 1.86 K kg mol–1)

17. 500 K †Öî ü 700 K ¯Ö¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÛúÖ ¤ü¸ü ×ãָüÖÓÛú ÛÎú´Ö¿Ö: 0.02 s–1 †Öî ü 0.07 s–1 Æîü … ÃÖ×ÛÎúµÖÞÖ

‰ú•ÖÖÔ, Ea ÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ … (R = 8.314 J K–1 mol–1)

The rate constants of a reaction at 500 K and 700 K are 0.02 s–1 and 0.07 s–1

respectively. Calculate the value of activation energy, Ea. (R = 8.314 J K–1 mol–1)

18. ×®Ö´®Ö ¯Ö¤üÖë ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(ii) †×¬Ö¿ÖÖêÂÖÞÖ

(iii) ¿Öê Ö-ÃÖê»Öê׌™ü¾Ö (†ÖÛéú×ŸÖ †Ö¬ÖÖ׸üŸÖ) ˆŸ¯ÖÏê üÞÖ

Define the following terms :

(i) Electrophoresis

(ii) Adsorption

(iii) Shape selective catalysis

Page 25: Chemistry Past Papers

56/1/3 6

19. ×®Ö´®Ö ×¾Ö׬ֵÖÖë «üÖ¸üÖ ¬ÖÖŸÖã†Öë Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûêú †Ö¬ÖÖ¸ü ´Öæ»Ö ×ÃÖ¨üÖ®ŸÖ ×»Ö×ÜÖ‹ :

(i) †ÖÃÖ¾Ö®Ö

(ii) •ÖÖê®Ö ¯Ö׸üÂÛú¸üÞÖ

(iii) ¾ÖîªãŸÖ †¯Ö‘Ö™ü®Ö

†£Ö¾ÖÖ

†ÖµÖ¸ü®Ö Ûêú ×®ÖÂÛúÂÖÔÞÖ Ûêú ÃÖ´ÖµÖ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë •ÖÖê †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü ˆ®Æëü ×»Ö×ÜÖ‹ … œü»Ö¾Öë

»ÖÖêÆêü ÃÖê Ûú““ÖÖ (Pig) »ÖÖêÆüÖ ÛîúÃÖê ׳֮®Ö ÆüÖêŸÖÖ Æîü ?

Outline the principles of refining of metals by the following methods :

(i) Distillation

(ii) Zone refining

(iii) Electrolysis

OR

Write down the reactions taking place in different zones in the blast furnace during the

extraction of iron. How is pig iron different from cast iron ?

20. »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö ŒµÖÖ Æîü ? »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö Ûêú ŒµÖÖ ¯Ö׸üÞÖÖ´Ö ÆüÖêŸÖê Æïü ?

What is lanthanoid contraction ? What are the consequences of lanthanoid contraction ?

21. ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖÖë «üÖ¸üÖ •ÖÖê ÃÖ´ÖÖ¾ÖµÖ¾ÖŸÖÖ Ûêú ¯ÖÏÛúÖ¸ü ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖê Æïü ˆ®ÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ‹×£Ö»Öß®Ö ›üÖ‡‹ê Öß®Ö)

(iii) [Pt(NH3)2Cl2]

Indicate the types of isomerism exhibited by the following complexes :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ethylene diamine)

(iii) [Pt(NH3)2Cl2]

Page 26: Chemistry Past Papers

56/1/3 7 [P.T.O.

22. ×®Ö´®Ö Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ¤üßו֋ :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

Name the following according to IUPAC system :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

23. ¸ü´Öê¿Ö ‹Ûú ×›ü¯ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ÝÖµÖÖ ¾ÖÆüÖÑ ˆÃÖê Ûãú”û ‘Ö¸ü Ûêú ×»ÖµÖê ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®ÖÖ £ÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ˆÃÖ®Öê ¿ÖãÝÖ¸ü- ±Ïúß ×™ü×ÛúµÖÖÑ ¤êüÜÖß … ˆÃÖ®Öê ˆ®Æëü †¯Ö®Öê ¤üÖ¤üÖ Ûêú ×»ÖµÖê ÜÖ¸üߤü®Öê ÛúÖ ×®ÖÞÖÔµÖ ×ÛúµÖÖ •ÖÖê ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ŸÖß®Ö ¯ÖÏÛúÖ¸ü Ûúß ¿ÖãÝÖ¸ü-±Ïúß ×™ü×ÛúµÖÖÑ ´ÖÖî•Öæ¤ü £Öà … ¸ü´Öê¿Ö ®Öê ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú þÖÖãµÖ Ûêú ×»ÖµÖê †“”ûß £Öà …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ±Ïúß ×™ü×ÛúµÖÖ ÛúÖ ˆ»»ÖêÜÖ Ûúßו֋ וÖÃÖê ¸ü´Öê¿Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ײ֮ÖÖ ›üÖòŒ™ü¸ü Ûúß ¯Ö“Öá Ûêú ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ŒµÖÖ ¸ü´Öê¿Ö Ûêú ×»Ö‹ ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ×¾Ö¾ÖÞÖÔ ÃÖê ¸ü´Öê¿Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖÖ Æîü ?

Ramesh went to a departmental store to purchase groceries. On one of shelves he

noticed sugar-free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar-free tablets. Ramesh decided to buy

sucrolose which was good for his grandfather’s health.

(i) Name another sugar free tablet which Ramesh did not buy.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Ramesh is reflected above ?

Page 27: Chemistry Past Papers

56/1/3 8

24. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤êüŸÖê Æãü‹ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ›üßÛúÖ²ÖÖì׌ÃÖ»ÖßÛú¸üÞÖ †×³Ö×ÛÎúµÖÖ

(ii) ±ÏúÖ‡›êü»Ö-ÛÎîú°™ü †×³Ö×ÛÎúµÖÖ

(b) †Ö¯Ö ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ²ÖꮕÖÌÖê‡Ûú †´»Ö ÛúÖê ²ÖꮕÖî×»›üÆüÖ‡›ü ´Öë

(ii) ²ÖꮕÖÌß®Ö ÛúÖê m-®ÖÖ‡™ÒüÖê‹ÃÖß™üÖ±úß®ÖÖê®Ö ´Öë

(iii) ‹£Öî®ÖÖò»Ö ÛúÖê 3-ÆüÖ‡›ÒüÖòŒÃÖß ²µÖæ™îü®Öî»Ö ´Öë

†£Ö¾ÖÖ

(a) ×®Ö´®Ö ×ÛÎúµÖÖ†Öë ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ‹ÃÖß×™ü»ÖßÛú¸üÞÖ

(ii) ‹ê»›üÖê»Ö ÃÖÓ‘Ö®Ö®Ö

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ †×³Ö×ÛÎúµÖÖ†Öë Ûêú ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ÛúÖê ×»Ö×ÜÖ‹ :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

(a) Describe the following giving chemical equations :

(i) De-carboxylation reaction

(ii) Friedel-Crafts reaction

(b) How will you bring about the following conversions ?

(i) Benzoic acid to Benzaldehyde

(ii) Benzene to m-Nitroacetophenone

(iii) Ethanol to 3-Hydroxybutanal

OR

Page 28: Chemistry Past Papers

56/1/3 9 [P.T.O.

(a) Describe the following actions :

(i) Acetylation (ii) Aldol condensation

(b) Write the main product in the following equations :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

25. (a) ×®Ö´®Ö ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

(i) Cu + HNO3(ŸÖ®Öã) →

(ii) P4 + NaOH+ H2O →

(b) (i) ŒµÖÖë R3P = O ²Ö®ÖŸÖÖ Æîü ¯Ö¸ü®ŸÖã R3N = O ®ÖÆüà ²Ö®ÖŸÖÖ Æîü ? (R = ‹×»Ûú»Ö ÝÖÏã Ö)

(ii) ›üÖ‡†ÖòŒÃÖß•Ö®Ö ŒµÖÖë ‹Ûú ÝÖîÃÖ Æîü ¯Ö¸ü®ŸÖã ÃÖ»±ú¸ü ‹Ûú šüÖêÃÖ Æîü ?

(iii) Æîü»ÖÖê•Ö®Ö ŒµÖÖë ÓüÝÖµÖãŒŸÖ ÆüÖêŸÖê Æïü ?

†£Ö¾ÖÖ

(a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»Ö‹ ÃÖÓŸÖã×»ÖŸÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ :

(i) ²Öã—Öê “Öæ®Öê Ûêú ÃÖÖ£Ö Œ»ÖÖê üß®Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü …

(ii) ÛúÖ²ÖÔ®Ö ÃÖÖÓ¦ü H2SO4 ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü …

(b) ÃÖ»°µÖæ׸üÛú †´»Ö ÛúÖê ÛúÖÓ™îüŒ™ü ×¾Ö×¬Ö ÃÖê ²Ö®ÖÖ®Öê ÛúÖ ×®Ö´®Ö ÃÖÓ¤ü³ÖÖí, •ÖîÃÖê †×¬ÖÛúŸÖ´Ö ˆŸ¯ÖÖ¤ü, ˆŸ¯ÖÏê üÞÖ †Öî ü †®µÖ ×ãÖ×ŸÖ ´Öë ¾ÖÞÖÔ®Ö Ûúßו֋ …

(a) Complete the following chemical reaction equations :

(i) Cu + HNO3(dilute) →

(ii) P4 + NaOH+ H2O →

Page 29: Chemistry Past Papers

56/1/3 10

(b) (i) Why does R3P = O exist but R3N = O does not ? (R = alkyl group)

(ii) Why is dioxygen a gas but sulphur a solid ?

(iii) Why are halogens coloured ?

OR

(a) Write balanced equations for the following reactions :

(i) Chlorine reacts with dry slaked lime.

(ii) Carbon reacts with concentrated H2SO4.

(b) Describe the contact process for the manufacture of sulphuric acid with special

reference to the reaction conditions, catalysts used and the yield in the process.

26. (a) ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ (^m)

(ii) ÃÖÓ“ÖÖµÖÛú ²Öî™ü׸üµÖÖÑ

(iii) ‡Õ¬Ö®Ö ÃÖê»Ö

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ ×®ÖµÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ :

(i) ±îú¸üÖ›êü Ûêú ¾ÖîªãŸÖ†¯Ö‘Ö™ü®Ö ÛúÖ ¯ÖÏ£Ö´Ö ×®ÖµÖ´Ö

(ii) ÛúÖê»Ö¸üÖ‰ú¿Ö Ûêú †ÖµÖ®ÖÖë Ûêú þ֟ÖÓ¡Ö †×³ÖÝÖ´Ö®Ö ÛúÖ ×®ÖµÖ´Ö

†£Ö¾ÖÖ

(a) ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ‹Ûú ¾µÖÓ•ÖÛú ×»Ö×ÜÖ‹ •ÖÖê ¤ãü²ÖÔ»Ö ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûúß ´ÖÖê»Ö¸ü

“ÖÖ»ÖÛúŸÖÖ ÛúÖê ‡ÃÖÛêú ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ÆüÖêŸÖÖ Æîü …

(b) ÃÖê»Ö †×³Ö×ÛÎúµÖÖ

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Ûêú ×»ÖµÖê 25 °C ¯Ö¸ü ŸÖã»µÖ ×ãָüÖÓÛú ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ … ‡ÃÖ ÃÖê»Ö Ûêú ÛúÖ´Ö Ûú¸ü®Öê ¯Ö¸ü †×¬ÖÛúŸÖ´Ö ×ÛúŸÖ®ÖÖ

ÛúÖµÖÔ ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü ?

E°Ni2+/Ni

= 0.25 V, E°Ag+/Ag

= 0.80 V.

Page 30: Chemistry Past Papers

56/1/3 11 [P.T.O.

(a) Define the following terms :

(i) Molar conductivity (^m)

(ii) Secondary batteries

(iii) Fuel cell

(b) State the following laws :

(i) Faraday first law of electrolysis

(ii) Kohlrausch’s law of independent migration of ions

OR

(a) Define the term degree of dissociation. Write an expression that relates the molar

conductivity of a weak electrolyte to its degree of dissociation.

(b) For the cell reaction

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Calculate the equilibrium constant at 25 °C. How much maximum work would

be obtained by operation of this cell ?

E°Ni2+/Ni

= 0.25 V and E°Ag+/Ag

= 0.80 V.

___________

Page 31: Chemistry Past Papers

56/1/3 12

Page 32: Chemistry Past Papers

1

Qu

es. Value points Marks

1 Hexaamninenickel (II) chloride 1

2

1

3

(where Ar is C6H5)

1

4 2 1

5 It is a process of removing a dissolved substance from a colloidal solution by means of diffusion

through a suitable membrane.

1

6

½

½

1

7 The external pressure which is applied on solution side to stop the flow of solvent across the

semi-permeable membrane.

The osmotic pressure is directly proportional to concentration of the solution. / = CRT

1

1

8 The half-life of a reaction is the time in which the concentration of a reactant is reduced to one-

half of its initial concentration.

Rate constant is the rate of reaction when the concentration of the reactant is unity.

1

1

CHEMISTRY MARKING SCHEME

SET -56/1/3

Compt. July, 2015

Page 33: Chemistry Past Papers

2

9

i) ii)

1+1

10 Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

OR

1

1

10 i) Due to presence of unpaired electrons in d-orbitals.

ii) Due to incomplete filling of d-orbitals.

1

1

11 i)

ii)

iii)

1

1

1

12

A – Benzoic acid

B – Benzamide

½ +

½

½ +

½

Page 34: Chemistry Past Papers

3

C - Aniline

½ +

½

13 Fat soluble vitamin- Vitamin A, D

Water soluble vitamin-Vitamin B,C

Vitamin K

½+½

½+½

1

14 i)

ii)

iii)

½ +

½

½ +

½

½ +

½

15 i) The defect in which equal number of cations and anions are missing from the lattice.

ii) Due to dislocation of smaller ion from its normal site to an interstitial site.

iii) Anionic vacancies are occupied by unpaired electron.

1

1

1

16 i) ∆Tf = Kf m

∆Tf = Kf

∆Tf =

∆Tf =2.325K or 2.3250

C

ii) Tf0- Tf = 2.325

0 C

O0C - Tf = 2.325

0 C

Tf = - 2.3250

C or 270.675 K

½

½

1

1

17

1

1

1

18 i) The movement of colloidal particles under an applied electric potential towards oppositely

charged electrode is called electrophoresis.

ii) The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid

1

1

Page 35: Chemistry Past Papers

4

is termed adsorption.

iii) The catalytic reaction that depends upon the pore structure of the catalyst and the size of the

reactant and product molecules is called shape-selective catalysis.

1

19 i) The impure metal is evaporated to obtain the pure metal as distillate.

ii) This method is based on the principle that the impurities are more soluble in the melt than in

the solid state of the metal.

iii) The impure metal is made to act as anode. A strip of the same metal in pure form is used as

cathode. They are put in a suitable electrolytic bath containing soluble salt of the same metal.

The more basic metal remains in the solution and the less basic ones go to the anode mud.

OR

1

1

1

19

( any four correct equations) Cast iron has lower carbon content (about 3%) than pig iron / cast iron is hard & brittle whereas pig iron is soft.

½ x 4

= 2

1

20 The steady decrease in atomic radii from La to Lu due to imperfect shielding of 4f – orbital.

Consequences –

i) Members of third transition series have almost identical radii as coresponding members

of second transition series.

ii) Difficulty in separation.

1

1+1

21 a) Linkage isomerism

b) Optical isomerism

c) Cis - trans / Geometrical isomerism

1

1

1

22 a) Butan – 2 – ol

b) 2 – bromotoluene

c) 2, 2-dimethylchlorpropane

1

1

1

23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2

24 a) i) Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are

heated with sodalime (NaOH and CaO).

ii) When the alkyl / acyl group is introduced at ortho and para positions by reaction

with alkyl halide / acyl halide in the presence of anhydrous aluminium chloride (a Lewis

acid) as catalyst.

1

Page 36: Chemistry Past Papers

5

(Note : Award full marks if correct equation is given )

b) i)

ii)

iii)

(or any other correct method)

OR

1

1

1

1

24 a) i) When the acyl groups are introduced at ortho and para positions by reaction with acyl halide in the

presence of anhydrous aluminium chloride (a Lewis acid) as catalyst.

ii) Aldehydes and ketones having at least one -hydrogen undergo a reaction in the presence of

dilute alkali as catalyst to form -hydroxy aldehydes (aldol) or hydroxy ketones (ketol),

respectively.

(Note : Award full marks if correct equation is given )

b)i)

1

1

1

Page 37: Chemistry Past Papers

6

ii)

iii) CH3COCl

1

1

25 a) i)

ii)

b) i) Due to absence of d-orbital, nitrogen cannot expand its valency beyond four.

ii) Because of pπ – pπ multiple bonding in dioxygen which is absent in sulphur.

iii) Due to excitation of electron by absorption of radiation from visible region. OR

1

1

1

1

1

25 a) i)

ii)

b) It is manufactured by Contact Process which involves following steps:

i) burning of sulphur or sulphide ores in air to generate SO2.

ii) conversion of SO2 to SO3 by the reaction with oxygen in the presence of a catalyst (V2O5)

iii) absorption of SO3 in H2SO4 to give Oleum (H2S2O7). The oleum obtained is diluted to give

sulphuric acid

Reaction condition – pressure of 2 bar and temperature of 720 K

Catalyst used is V2O5

Yield – 96 – 98% pure

1

1

1

1

1

26 a)i)Molar conductivity of a solution at a given concentration is the conductance of the volume V

of solution containing one mole of electrolyte kept between two electrodes with area of cross

section A and distance of unit length.

ii) Secondary battery- can be recharged by passing current through it in opposite direction so that

it can be used again.

iii) Galvanic cells that are designed to convert the energy of combustion of fuels like hydrogen,

methane, methanol, etc. directly into electrical energy are called fuel cells.

b)i) The amount of chemical reaction which occurs at any electrode during electrolysis by a

current is proportional to the quantity of electricity passed through the electrolyte (solution or

melt).

ii) Limiting molar conductivity of an electrolyte can be represented as the sum of the individual

contributions of the anion and cation of the electrolyte.

OR

1

1

1

1

1

26 a) Degree of dissociation is the extent to which electrolyte gets dissociated into its constituent

ions.

b) E

0cell = E

0Ag+ / Ag - E

0Ni2+ / Ni

= 0.80V – 0.25V

1

1

Page 38: Chemistry Past Papers

7

Dr. Sangeeta Bhatia Sh. S.K. Munjal Sh. D.A. Mishra

Ms. Garima Bhutani

= 0.55V

1og Kc =

=

log Kc = 18.644

∆G0 = - nFE

0cell

= -2x96500 Cmol-1

x 0.55V

= -106,150 Jmol-1

Max.work =+106150 Jmol-1

or 106.150k Jmol-1

½

½

½

½

1

Page 39: Chemistry Past Papers

56/2 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

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×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ŸÖÛú ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛúŸÖÖ ÆüÖê, ŸÖÖê »ÖÖòÝÖ ™êü²Ö»ÖÖë ÛúÖ ¯ÖϵÖÖêÝÖ Ûú¸ëü … Ûîú»ÖÛãú»Öê™ü¸üÖë Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/C 56/2

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 12 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 2

Page 40: Chemistry Past Papers

56/2 2

General Instructions :

(i) All questions are compulsory.

(ii) Question number 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Question number 6 to 10 are short answer questions and carry 2 marks each.

(iv) Question number 11 to 22 are also short answer questions and carry 3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Question number 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. ‡´Ö»¿Ö®Ö ŒµÖÖ ÆüÖêŸÖê Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

What are emulsions ? Give an example.

2. ‘Ûúß»Öê™’ü ¯ÖϳÖÖ¾Ö ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

What is meant by chelate effect ?

3. ×®Ö´®Ö ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

CH3 – CH2 – CHO

Write the IUPAC name of the following :

CH3 – CH2 – CHO

4. ×®Ö´®Ö ÛúÖê õÖÖ¸üßµÖ õÖ´ÖŸÖÖ Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ¾µÖ¾Ö×Ã£ÖŸÖ Ûúßו֋ :

‹ê×®Ö»Öß®Ö, p-®ÖÖ‡™ÒüÖê‹ê×®Ö»Öß®Ö †Öî ü p-™üÖ»Ö㇛Ìüß®Ö

Arrange the following in increasing order of basic strength :

Aniline, p-Nitroaniline and p-Toluidine

5. AgCl ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ Ã™üÖê‡×ÛúµÖÖê Öß™Òüß ¤üÖêÂÖ ¤ü¿ÖÖÔŸÖÖ Æîü ?

What type of stoichiometric defect is shown by AgCl ?

Page 41: Chemistry Past Papers

56/2 3 [P.T.O.

6. ×®Ö´®Ö Ûú£Ö®ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ±úÖòñúÖê üÃÖ Ûúß †¯ÖêõÖÖ ®ÖÖ‡™ÒüÖê•Ö®Ö ²ÖÆãüŸÖ Ûú´Ö ÃÖ×ÛÎúµÖ Æîü …

(ii) NF3 ‹Ûú ‰ú´ÖÖõÖê Öß ¯Ö¤üÖ£ÖÔ Æîü ¯Ö¸ü®ŸÖã NCl3 ‰ú´ÖÖ¿ÖÖêÂÖß ¯Ö¤üÖ£ÖÔ Æîü …

Explain the following :

(i) Nitrogen is much less reactive than phosphorus.

(ii) NF3 is an exothermic compound but NCl3 is an endothermic compound.

7. ¯ÖÖê™îü×¿ÖµÖ´Ö ¯Ö¸ü´ÖïÝÖ®Öê™ü Ûúß ×®Ö´ÖÖÔÞÖ ×¾Ö×¬Ö ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ … †´»ÖßÛéúŸÖ ¯Ö¸ü´ÖîÓÝÖ®Öê™ü †ÖòŒÃÖî×»ÖÛú †´»Ö Ûêú ÃÖÖ£Ö ÛîúÃÖê

†×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ? †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ …

†£Ö¾ÖÖ

¯ÖÖê™îü×¿ÖµÖ´Ö ›üÖ‡ÛÎúÖê Öê™ü Ûúß †ÖòŒÃÖßÛú¸üÞÖ ×ÛÎúµÖÖ ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ †Öî ü ‡ÃÖÛúß (i) †ÖµÖÖê›üÖ‡›ü (ii) H2S Ûêú ÃÖÖ£Ö

ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ×»Ö×ÜÖ‹ …

Describe the preparation of potassium permanganate. How does the acidified

permanganate solution react with oxalic acid ? Write the ionic equations for the

reactions.

OR

Describe the oxidising action of potassium dichromate and write the ionic equations

for its reaction with (i) an iodide (ii) H2S.

8. ‹£Öî®ÖÖò»Ö ÃÖê ‹£Öß®Ö ²Ö®Ö®Öê ´Öë †´»Ö ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ×ÛÎúµÖÖ×¾Ö×¬Ö ×»Ö×ÜÖ‹ …

Write the mechanism of acid dehydration of ethanol to yield ethene.

9. ×®Ö´®Ö ¯Ö¤üÖë Ûúß ¯Ö׸ü³ÖÖÂÖÖ‹Ñ ×»Ö×ÜÖµÖê :

(i) ´ÖÖê»ÖÖÓ¿Ö (x)

(ii) ‹Ûú ×¾Ö»ÖµÖ®Ö Ûúß ´ÖÖê»Ö»ÖŸÖÖ (m)

Define the following terms :

(i) Mole fraction (x)

(ii) Molality of a solution (m)

Page 42: Chemistry Past Papers

56/2 4

10. •Ö߸üÖê †Öò›Ôü¸ü †Öî ü ׫üŸÖßµÖ †Öò›Ôü¸ü †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛúÖë Ûêú µÖæ×®Ö™ü ×»Ö×ÜÖ‹ ˆÃÖ ×ãÖ×ŸÖ ´Öë •Ö²Ö ÃÖÖÓ¦üŸÖÖ

ÛúÖê mol L–1 †Öî ü ÃÖ´ÖµÖ ÛúÖê ÃÖêÛúÞ›üÖë ´Öë ×»ÖÜÖÖ ÝÖµÖÖ ÆüÖê …

Write units of rate constants for zero order and for the second order reactions if the

concentration is expressed in mol L–1 and time in second.

11. ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ‹ê»Öã×´Ö×®ÖµÖ´Ö Ûêú ¬ÖÖŸÖãÛú´ÖÔ ´Öë ÛÎúÖ‡µÖÖê»ÖÖ‡™ü Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(ii) ³Ö•ÖÔ®Ö ×ÛÎúµÖÖ †Öî ü ×®ÖßÖÖ¯Ö®Ö ´Öë †ÓŸÖ¸ü Ûúßו֋ …

(iii) ‘ÛÎúÖê Öîê™üÖêÝÖÏî±úß’ ¯Ö¤ü ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

†£Ö¾ÖÖ

»ÖÖêÆüÖ ²Ö®ÖÖ®Öê Ûêú ×»Ö‹ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë ´Öë ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ‹Ñ ×»Ö×ÜÖ‹ …

Answer the following :

(i) What is the role of cryolite in the metallurgy of aluminium ?

(ii) Differentiate between roasting and calcination.

(iii) What is meant by the term ‘chromatography’ ?

OR

Write the reactions taking place in different zones of the blast furnace to obtain Iron.

12. ‘†®ÖÖ®Öã ÖÖŸÖ®Ö’ ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ‹Ûú ˆ¤üÖÆü üÞÖ ¤üßו֋ …

What is meant by ‘disproportionation’ ? Give one example of disproportionation

reaction in aqueous solutions.

13. ×®Ö´®Ö×»Ö×ÜÖŸÖ Ûêú IUPAC ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

Write the IUPAC name of the following :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

Page 43: Chemistry Past Papers

56/2 5 [P.T.O.

14. ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ¤üßו֋ :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

Give the IUPAC names of the following compounds :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

15. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ²Öê×®•Ö»Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ²Öê×®•Ö»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë

(ii) ‹×£Ö»Ö ´ÖîÝ®Öß×¿ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ¯ÖÏÖê Öê®Ö-1-†Öò»Ö ´Öë

(iii) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë

How are the following conversions carried out ?

(i) Benzyl chloride to Benzyl alcohol

(ii) Ethyl magnesium chloride to Propan-1-ol

(iii) Propene to Propan-2-ol

Page 44: Chemistry Past Papers

56/2 6

16. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ×»Ö×ÜÖ‹ :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

Write the major product in the following equations :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

17. ¯ÖÏÖê™üß®Ö ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ×®Ö´®Ö ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¯Öê ™üÖ‡›ü Ø»ÖÛêú•Ö

(ii) ¯ÖÏÖ‡´Ö¸üß ÃÖÓ ü“Ö®ÖÖ

(iii) ›üß®Öî“Öã êü¿Ö®Ö

Define the following as related to proteins :

(i) Peptide linkage

(ii) Primary structure

(iii) Denaturation

18. ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ ¯Ö¤ü Ûúß ¾µÖÖܵÖÖ Ûúßו֋ †Öî ü ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ Ûêú ¤üÖê ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

Explain the term ‘copolymerization’ and give two examples of copolymerization.

Page 45: Chemistry Past Papers

56/2 7 [P.T.O.

19. ×ÃÖ»¾Ö¸ü fcc •ÖÖ»ÖÛú ´Öë ×ÛÎúÙü×»ÖŸÖ ÆüÖêŸÖÖ Æîü … µÖפü µÖæ×®Ö™ü ÃÖê»Ö Ûêú ÛúÖê ü Ûúß »Ö´²ÖÖ‡Ô 4.077 × 10–8 cm ÆüÖê, ŸÖÖê

×ÃÖ»¾Ö¸ü ÛúÖ †¬ÖÔ¾µÖÖÃÖ (r) ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

Silver crystallises in fcc lattice. If edge length of the unit cell is 4.077 × 10–8 cm, then

calculate the radius of silver atom.

20. Ûêú®Ö-¿ÖãÝÖ¸ü (M.W. 342) ÛúÖ 5 ¯ÖÏ×ŸÖ¿ÖŸÖ ‘ÖÖê»Ö (¦ü¾µÖ´ÖÖ®Ö †Ö¬ÖÖ¸ü ¯Ö¸ü) ‹Ûú ¯Ö¤üÖ£ÖÔ X Ûêú 0.877% ‘ÖÖê»Ö Ûêú ÃÖÖ£Ö

†Ö‡ÃÖÖê™üÖê×®ÖÛú Æîü … X ÛúÖ †ÖÞÖ×¾ÖÛú ³ÖÖ¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

A 5 percent solution (by mass) of cane-sugar (M.W. 342) is isotonic with 0.877%

solution of substance X. Find the molecular weight of X.

21. ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛú 60 s–1 Æîü … †×³ÖÛúÖ¸üÛú Ûêú ¯ÖÏÖ¸ü×´³ÖÛú ÃÖÖÓ¦üÞÖ ÛúÖê ‡ÃÖÛêú 1/10

ŸÖÛú ‘Ö™®Öêê ´Öë ×ÛúŸÖ®ÖÖ ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ?

The rate constant for a first order reaction is 60 s–1. How much time will it take to

reduce the initial concentration of the reactant to its 1/10th

value ?

22. ×®Ö´®Ö ¯ÖÏÛÎú´ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ›üÖµÖ×»Ö×ÃÖÃÖ

(ii) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(iii) ×™üÞ›ü»Ö ¯ÖϳÖÖ¾Ö

Describe the following processes :

(i) Dialysis

(ii) Electrophoresis

(iii) Tyndall effect

Page 46: Chemistry Past Papers

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23. ®Ö߸ü•Ö ×›ü ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ‘Ö¸ü Ûêú ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®Öê Ûêú ×»ÖµÖê ÝÖµÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ¾ÖÆü Ûãú”û ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ

¤êüÜÖÖ … ¾ÖÆü Ûãú”û ‹êÃÖß ×™ü×ÛúµÖÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß, ŒµÖÖë×Ûú ˆÃÖÛêú

¤üÖ¤üÖ ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ¾ÖÆüÖÑ ŸÖß®Ö ¯ÖÏÛúÖ¸ü Ûúß ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ £ÖßÓ … ˆÃÖ®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ¾ÖÆü ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤêü

•ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ¸ü×ÆüŸÖ ÛúÖ ®ÖÖ´Ö ¤üßו֋ •ÖÖê ®Ö߸ü•Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ŒµÖÖ ›üÖŒ™ü¸ü Ûêú ¯Ö“Öá Ûêú ײ֮ÖÖ ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ®Ö߸ü•Ö Ûêú ×»ÖµÖê ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ÃÖê ®Ö߸ü•Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖÏןֻÖ×õÖŸÖ ÆüÖêŸÖÖ Æîü ?

Neeraj went to the departmental store to purchase groceries. On one of the shelves he

noticed sugar free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar free tablets. He decided to buy sucrolose

which was good for his grandfather’s health.

(i) Name another sugar free tablet which Neeraj did not purchase.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Neeraj is reflected above ?

24. (a) ÝÖÏã Ö 16 Ûêú ŸÖ¢¾Ö ÃÖÖ¬ÖÖ¸üÞÖŸÖµÖÖ ¯ÖÏ£Ö´Ö †ÖµÖ®Ö®Ö ‹®£ÖÖß ŸÖŸÃÖ´²Ö®¬Öß †Ö¾ÖŸÖÔ ¾ÖÖ»Öê ÝÖÏã Ö 15 Ûêú ŸÖ¢¾ÖÖë Ûúß

ŸÖã»Ö®ÖÖ ´Öë Ûú´Ö ´ÖÖ®Ö ¤ü¿ÖÖÔŸÖê Æïü … ‹êÃÖÖ ŒµÖÖë Æîü ?

(b) ŒµÖÖ ÆüÖêŸÖÖ Æîü •Ö²Ö –

(i) ÃÖÖÓ¦ü H2SO4 ÛúÖê CaF2 ¯Ö¸ü ›üÖ»ÖÖ •ÖÖŸÖÖ Æîü ?

(ii) ÃÖ»±Ìú¸ü ›üÖ‡†ÖòŒÃÖÖ‡›ü “ÖÖ¸üÛúÖê»Ö Ûúß ˆ¯Ö×ãÖ×ŸÖ ´Öë Œ»ÖÖê üß®Ö ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü ?

(iii) †´ÖÖê×®ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖê Ca(OH)2 Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ×ÛúµÖÖ •ÖÖŸÖÖ Æîü ?

†£Ö¾ÖÖ

Page 47: Chemistry Past Papers

56/2 9 [P.T.O.

(a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) BrF3

(ii) XeO3

(b) ×®Ö´®Ö ¯ÖÏ¿®ÖÖë Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) PH3Ûúß †¯ÖêõÖÖ NH3 ŒµÖÖë †×¬ÖÛú õÖÖ¸üßµÖ ÆüÖêŸÖÖ Æîü ?

(ii) Æîü»ÖÖê•Ö®Ö ¯ÖÏ²Ö»Ö †ÖòŒÃÖßÛúÖ¸üÛú ŒµÖÖë ÆüÖêŸÖê Æïü ?

(iii) XeOF4 Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

(a) Elements of Gr. 16 generally show lower value of first ionization enthalpy

compared to the corresponding periods of Gr. 15. Why ?

(b) What happens when

(i) concentrated H2SO4 is added to CaF2 ?

(ii) sulphur dioxide reacts with chlorine in the presence of charcoal ?

(iii) ammonium chloride is treated with Ca(OH)2 ?

OR

(a) Draw the structure of the following :

(i) BrF3

(ii) XeO3

(b) Answer the following :

(i) Why is NH3 more basic than PH3 ?

(ii) Why are halogens strong oxidising agents ?

(iii) Draw the structure of XeOF4.

Page 48: Chemistry Past Papers

56/2 10

25. (a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) p-´Öê×£Ö»Ö²Öï•Ö̋׻›üÆüÖ‡›ü

(ii) 4-´Öê×£Ö»Ö¯Öî®™ü-3-‡Ô®Ö-2-†Öò®Ö

(b) ×®Ö´®Ö µÖÖî×ÝÖÛú µÖãÝ´ÖÖë ´Öë †ÓŸÖ¸ü Ûú¸ü®Öê Ûêú ×»ÖµÖê ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“ÖÖë ÛúÖê ¤üßו֋ :

(i) ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü †Öî ü ‹×£Ö»Ö²ÖꮕÖÌÖê‹™ü …

(ii) ²ÖꮕÖî×»›üÆüÖ‡›ü †Öî ü ‹êÃÖß™üÖê±úß®ÖÖê®Ö

(iii) ±úß®ÖÖò»Ö †Öî ü ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü

†£Ö¾ÖÖ

(a) ×®Ö´®Ö ¾µÖ㟯֮®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö¸êü×ÜÖŸÖ Ûúßו֋ :

(i) ¯ÖÏÖê Öê®ÖÖê®Ö †Öò׌ÃÖ´Ö

(ii) CH3CHO ÛúÖ ÃÖê ÖßÛúÖ²Öì•ÖÖê®Ö

(b) ‹£Öî®ÖÖò»Ö ÛúÖê †Ö¯Ö ×®Ö´®Ö µÖÖî×ÝÖÛúÖë ´Öë ÛîúÃÖê ºþ¯ÖÖÓŸÖ׸üŸÖ Ûú ëüÝÖê ? ÃÖ´Ö²Ö¨ü ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤üßו֋ …

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

(a) Draw the structures of the following :

(i) p-Methylbenzaldehyde

(ii) 4-Methylpent-3-en-2-one

(b) Give chemical tests to distinguish between the following pairs of compounds :

(i) Benzoic acid and Ethyl benzoate.

(ii) Benzaldehyde and Acetophenone.

(iii) Phenol and Benzoic acid.

OR

Page 49: Chemistry Past Papers

56/2 11 [P.T.O.

(a) Draw the structures of the following derivatives :

(i) Propanone oxime

(ii) Semicarbazone of CH3CHO

(b) How will you convert ethanal into the following compounds ? Give the chemical

equations involved.

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

26. ∆rG° †Öî ü e.m.f.(E) ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ •ÖÖê 25 °C ¯Ö¸ü Ùïü›ü›Ôü ×ãÖ×ŸÖ ´Öë ×®Ö´®Ö ÃÖê»Ö ÃÖê ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

פüµÖÖ ÝÖµÖÖ : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

†Öî ü F = 96500 C mol–1

†£Ö¾ÖÖ

(a) ‹Ûú ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûêú ×¾Ö»ÖµÖ®Ö Ûêú ×»ÖµÖê “ÖÖ»ÖÛúŸÖÖ †Öî ü ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

ÃÖÖÓ¦üŸÖÖ Ûêú ÃÖÖ£Ö ˆ®ÖÛêú ¯Ö׸ü¾ÖŸÖÔ®Ö Ûúß ¾µÖÖܵÖÖ Ûúßו֋ …

(b) ˆÃÖ ÝÖî»Ö¾ÖÖò×®ÖÛú ÃÖê»Ö Ûêú Ùïü›ü›Ôü ÃÖê»Ö ×¾Ö³Ö¾Ö ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ וÖÃÖ´Öë ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÆüÖêŸÖß Æîü :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

†×³Ö×ÛÎúµÖÖ ÛúÖ ∆rG° †Öî ü ŸÖ㻵ÖÖÓÛúß ×ãָüÖÓÛú ÛúÖ ¯Ö׸üÛú»Ö®Ö ³Öß Ûúßו֋ …

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

Page 50: Chemistry Past Papers

56/2 12

Calculate ∆rG° and e.m.f. (E) that can be obtained from the following cell under the

standard conditions at 25 °C :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

Given : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

and F = 96500 C mol–1.

OR

(a) Define conductivity and molar conductivity for the solution of an electrolyte.

Discuss their variation with concentration.

(b) Calculate the standard cell potential of the galvanic cell in which the following

reaction takes place :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

Calculate the ∆rG° and equilibrium constant of the reaction also.

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

____________

Page 51: Chemistry Past Papers

1

Qu

es. Value points Marks

1 Emulsions are liquid – liquid colloidal systems.

For example – milk, cream (or any other one correct example)

½ + ½

2 Formation of stable complex by polydentate ligand. 1

3 Propanal 1

4 p-Nitroaniline < Aniline < p-Toluidine 1

5 Frenkel defect 1

6 i) Due to high bond dissociation enthalpy of N N

ii) Due to low bond dissociation enthalpy of F2 than Cl2 and strong bond formation

between N and F

1

1

7 Potassium permanganate is prepared by fusion of MnO2 with an alkali metal hydroxide and an

oxidising agent like KNO3. This produces the dark green K2MnO4 which disproportionates in a

neutral or acidic solution to give permanganate.

Oxalate ion or oxalic acid is oxidised at 333 K:

OR

1

1

7 i)

ii)

1

1

8

½

½

1

CHEMISTRY MARKING SCHEME

SET -56/2

Compt. July, 2015

Page 52: Chemistry Past Papers

2

9 i)

ii) Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the

solvent. Or

1

1

10 Zero order : mol L-1

s-1

Second order : L mol-1

s-1

1

1

11 i) It lowers the melting point of alumina / acts as a solvent.

ii)

Roasting Calcination

Ore is heated in a regular supply of air Heating in a limited supply or

absence of air.

(Or with equation)

iii) It is a process of separation of different components of a mixture which are differently

adsorbed on a suitable adsorbent. OR

1

1

1

11

(any 6 correct equations)

6 x ½

= 3

12 Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

1 ½

1 ½

13 i) Hexaamminecobalt(III) chloride

ii) Tetrachlorido nickelate(II)

iii) Potassium hexacyanoferrate(III)

1

1

1

Page 53: Chemistry Past Papers

3

14 i) 2-bromobutane

ii) 1, 3-dibromobenzene

iii) 3-choloropropene

1

1

1

15

i)

ii)

1

1

1

16

i)

ii)

iii)

1

1

1

17 i) Peptide linkage – in proteins, -amino acids are connected to each other by peptide

bond or peptide linkage (-CONH- bond).

ii) Primary structure - each polypeptide in a protein molecule having amino acids which

are linked with each other in a specific sequence.

iii) Denaturation - When a protein is subjected to physical change like change in

temperature or chemical change like change in pH, protein loses its biological activity.

1

1

1

18 Copolymerisation is a polymerisation reaction in which a mixture of more than one monomeric

species is allowed to polymerise and form a copolymer.

1

1

Page 54: Chemistry Past Papers

4

(or any other correct example)

1

19 r =

r=

r = 1.44 x cm

1

1

1

cane sugar = πXח 20

Therefore, ccane sugar = cX (where c is molar concentration)

=

=

MX =

gmol

-1

MX = 59.9 or 60 gmol-1

1

1

1

21 k=

log

60 s-1

=

log

t=

log 10

t=

s

t= 0.0384 s

1

1

1

22 i) It is a process of removing the dissolved substance from a colloidal solution by means

of diffusion through a semi - permeable membrane.

ii) The movement of colloidal particles under an applied electric potential towards

oppositely charged electrode is called electrophoresis.

iii) Colloidal particles scatter light in all directions in space. This scattering of light

illuminates the path of beam in the colloidal dispersion.

1

1

1 23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2 24 a) Due to relatively stable half – filled p-orbitals of group 15 elements

b) i) CaF2 + H2SO4 CaSO4 + 2HF

ii)

iii)

OR

2

1

1

1

Page 55: Chemistry Past Papers

5

24 a) i)

ii)

b) i)Due to small size of nitrogen, the lone pair of electron on nitrogen is localized/ easily

available for donation.

ii)Because they need only one electron to attain stable/noble gas configuration.

iii)

1

1

1

1

1

25 a) i)

ii)

b) i)Add NaHCO3, benzoic acid will give brisk effervescence of CO2 whereas ethylbenzoate

will not.

ii)Add NaOH and I2, acetophonone forms yellow ppt of iodoform on heating whereas

benzaldehyde will not.

iii)Add neutral FeCl3, phenol gives violet colouration whereas benzoic acid does not.

1

1

1

1

Page 56: Chemistry Past Papers

6

(or any other correct test)

OR 1

25 a) i)

ii)

b) i)

ii)

iii)

1

1

1

1

1

26 E0cell = E

0Sn2+ / Sn - E

0Zn2+ / Zn

= - 0.14V –(- 0.76V)

= 0.62V

∆rG0 = -n F E

0cell

= - 2 x 96500 C mol-1

x 0.62 V

= - 119660 J mol-1

Ecell = E0

cell -

log

Ecell = 0.62 -

log

OR

1

1

1

1

1

26 a) The conductivity of a solution at any given concentration is the conductance of one unit

volume of solution kept between two platinum electrodes with unit area of cross section

and at a distance of unit length.

Molar conductivity of a solution at a given concentration is the conductance of the volume

V of solution containing one mole of electrolyte kept between two electrodes with area of

cross section A and distance of unit length.

Molar conductivity increases with decrease in concentration.

½

½

1

Page 57: Chemistry Past Papers

7

Dr. Sangeeta Bhatia Sh. S.K. Munjal Sh. D.A. Mishra

Ms. Garima Bhutani

b)E0cell = E

0C - E

0A

= 0.80V – 0.77V

= 0.03V

∆rG0 = -n F E

0cell

= - 1 x 96500 C mol-1

x 0.03 V

= - 2895 J mol-1

Log Kc=

Log Kc=

Log Kc= 0.508

½

½

1

½

½

Page 58: Chemistry Past Papers

56/1/2 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸ü ÃÖ Ö µÖ ®Ö × ¾Ö – Ö Ö ®Ö (ÃÖî ü Ö × ®ŸÖ Û ú ) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú »ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1/C 56/1/2

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 11 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 11 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 2

Page 59: Chemistry Past Papers

56/1/2 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. No. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. No. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. No. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. No. 23 is a value based question and carry 4 marks.

(vi) Q. No. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculator is not allowed.

1. ÃÖŸÖÆü ¸üÃÖÖµÖ®Ö Ûêú ÃÖÓ¤ü³ÖÔ ´Öë ›üÖµÖÖ×»Ö×ÃÖÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

In reference to surface chemistry, define dialysis.

2. ÛúÖò ¯»ÖêŒÃÖ [Ni(NH3)6]Cl2 ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ …

What is the IUPAC name of the complex [Ni(NH3)6]Cl2 ?

3. ×®Ö´®Ö µÖÖî×ÝÖÛú Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

3-´Öê×£Ö»Ö¯Öê®™îü®Öî»Ö

Draw the structure of 3-methylpentanal.

4. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

Complete the following reaction equation :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

5. ‹Ûú †ÓŸÖ: Ûêú×®¦üŸÖ ‘Ö®ÖßµÖ ÃÖÓ ü“Ö®ÖÖ ´Öë ¯Ö¸ü´ÖÖÞÖã†Öë Ûúß ÃÖÓܵÖÖ ¯ÖÏ×ŸÖ ‹ÛúÛú ÛúÖêךüÛúÖ (z) ŒµÖÖ ÆüÖêŸÖß Æîü ?

What is the no. of atoms per unit cell (z) in a body-centred cubic structure ?

Page 60: Chemistry Past Papers

56/1/2 3 [P.T.O.

6. ‘†ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö’ ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ ÛúÖ ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

†£Ö¾ÖÖ

ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã ¸üÃÖÖµÖ®Ö Ûêú ×®Ö´®Ö »ÖõÖÞÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ÃÖã—ÖÖ‡‹ :

(i) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ †Öî ü ˆ®ÖÛêú µÖÖî×ÝÖÛú ÃÖÖ´ÖÖ®µÖŸÖÖ †®Öã“Öã ²ÖÛúßµÖ ÆüÖêŸÖê Æïü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¯Ö׸ü¾ÖŸÖÔ®Ö¿Öᯙ ˆ¯Ö“ÖµÖ®Ö †¾ÖãÖÖ‹Ñ ¯ÖϤüÙ¿ÖŸÖ Ûú¸üŸÖß Æïü …

What is meant by ‘disproportionation’ ? Give an example of a disproportionation

reaction in aqueous solution.

OR

Suggest reasons for the following features of transition metal chemistry :

(i) The transition metals and their compounds are usually paramagnetic.

(ii) The transition metals exhibit variable oxidation states.

7. ‹£Öî®ÖÖò»Ö Ûêú ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ¯ÖÏ×ÛÎúµÖÖ Ûêú “Ö¸üÞÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

Explain the mechanism of dehydration steps of ethanol :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

8. ×¾Ö»ÖµÖ®Ö Ûêú ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛúÖê ¯Ö× ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾Ö»ÖµÖ®Ö ´Öë ×¾Ö»ÖêµÖ Ûêú ÃÖÖÓ¦üÞÖ ÃÖê ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛîúÃÖê ÃÖÓ²Ö×®¬ÖŸÖ Æîü ?

Define osmotic pressure of a solution. How is the osmotic pressure related to the

concentration of a solute in a solution ?

9. ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) †×³Ö×ÛÎúµÖÖ Ûúß †¬ÖÖÔµÖã (t½)

(ii) ¾ÖêÝÖ ×ãָüÖÓÛú (k)

Define the following terms :

(i) Half-life of a reaction (t½)

(ii) Rate constant (k)

Page 61: Chemistry Past Papers

56/1/2 4

10. ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) H2SO4

(ii) XeF2

Draw the structures of the following :

(i) H2SO4

(ii) XeF2

11. ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖÖë «üÖ¸üÖ •ÖÖê ÃÖ´ÖÖ¾ÖµÖ¾ÖŸÖÖ Ûêú ¯ÖÏÛúÖ¸ü ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖê Æïü ˆ®ÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ‹×£Ö»Öß®Ö ›üÖ‡‹ê Öß®Ö)

(iii) [Pt(NH3)2Cl2]

Indicate the types of isomerism exhibited by the following complexes :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ethylene diamine)

(iii) [Pt(NH3)2Cl2]

12. ×®Ö´®Ö Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ¤üßו֋ :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

Page 62: Chemistry Past Papers

56/1/2 5 [P.T.O.

Name the following according to IUPAC system :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

13. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë …

(ii) ²Öê×®•ÖÌ»Ö Œ»ÖÖê üÖ‡›ü ÛúÖê ²Öê×®•ÖÌ»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë …

(iii) ‹ê×®ÖÃÖÖê»Ö ÛúÖê p-²ÖÎÖê ÖÖê‹ê×®ÖÃÖÖê»Ö ´Öë …

How are the following conversions carried out ?

(i) Propene to propane-2-ol

(ii) Benzyl chloride to Benzyl alcohol

(iii) Anisole to p-Bromoanisole

14. ‹Ûú ‹ê üÖê Öî×™üÛú µÖÖî×ÝÖÛú ‘A’ •Ö»ÖßµÖ †´ÖÖê×®ÖµÖÖ Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ÆüÖê®Öê †Öî ü ÝÖ´ÖÔ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘B’ ²Ö®ÖÖŸÖÖ Æîü

•ÖÖê Br2 †Öî ü KOH Ûêú ÃÖÖ£Ö ŸÖÖ×¯ÖŸÖ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘C’ ²Ö®ÖÖŸÖÖ Æîü … ‘C’ ÛúÖ †ÖÞÖ×¾ÖÛú ÃÖæ¡Ö C6H7N Æîü …

A, B †Öî ü C µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ

Ûúßו֋ …

An aromatic compound ‘A’ on treatment with aqueous ammonia and heating forms

compound ‘B’ which on heating with Br2 and KOH forms a compound ‘C’ of

molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B

and C.

Page 63: Chemistry Past Papers

56/1/2 6

15. ×¾Ö™üÖ×´Ö®Öë ÛîúÃÖê ¾ÖÝÖáÛéúŸÖ Ûúß •ÖÖŸÖß Æïü ? ¸üŒŸÖ Ûêú ÃÛÓú¤ü®Ö Ûêú •ÖÖê ×¾Ö™üÖ×´Ö®Ö ˆ¢Ö¸ü¤üÖµÖß ÆüÖêŸÖê Æïü ˆ®ÖÛêú ®ÖÖ´Ö ¤üßו֋ …

How are vitamins classified ? Name the vitamin responsible for the coagulation of

blood.

16. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) ²Öæ®ÖÖ-S

(ii) ®Ö߆Öê ÖÏß®Ö

(iii) ™êü°»ÖÖò®Ö

Write the names and structures of the monomers of the following polymers :

(i) Buna-S

(ii) Neoprene

(iii) Teflon

17. ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¿ÖÖò™üÛúß ¤üÖêÂÖ

(ii) ±ÏëúÛêú»Ö ¤üÖêÂÖ

(iii) F-Ûëú¦ü

Define the following :

(i) Schottky defect

(ii) Frenkel defect

(iii) F-centre

18. ‹×£Ö»Öß®Ö Ý»ÖÖ‡ÛúÖê»Ö (C2H4O2) ÛúÖ 45 g •Ö»Ö Ûêú 600 g Ûêú ÃÖÖ£Ö ×´Ö»ÖÖµÖÖ ÝÖµÖÖ Æîü … ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(i) ×Æü´ÖÖÓÛú ÛúÖ †¾Ö®Ö´Ö®Ö †Öî ü

(ii) ×¾Ö»ÖµÖ®Ö ÛúÖ ×Æü´ÖÖÓÛú

(פüµÖÖ ÝÖµÖÖ Æîü : Kf ÛúÖ ´ÖÖ®Ö ¯ÖÖ®Öß Ûêú ×»Ö‹ = 1.86 K kg mol–1)

45 g of ethylene glycol (C2H4O2) is mixed with 600 g of water. Calculate

(i) the freezing point depression and

(ii) the freezing point of the solution

(Given : Kf of water = 1.86 K kg mol–1)

Page 64: Chemistry Past Papers

56/1/2 7 [P.T.O.

19. 500 K †Öî ü 700 K ¯Ö¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÛúÖ ¤ü¸ü ×ãָüÖÓÛú ÛÎú´Ö¿Ö: 0.02 s–1 †Öî ü 0.07 s–1 Æîü … ÃÖ×ÛÎúµÖÞÖ

‰ú•ÖÖÔ, Ea ÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ … (R = 8.314 J K–1 mol–1)

The rate constants of a reaction at 500 K and 700 K are 0.02 s–1 and 0.07 s–1

respectively. Calculate the value of activation energy, Ea. (R = 8.314 J K–1 mol–1)

20. ×®Ö´®Ö ¯Ö¤üÖë ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(ii) †×¬Ö¿ÖÖêÂÖÞÖ

(iii) ¿Öê Ö-ÃÖê»Öê׌™ü¾Ö (†ÖÛéú×ŸÖ †Ö¬ÖÖ׸üŸÖ) ˆŸ¯ÖÏê üÞÖ

Define the following terms :

(i) Electrophoresis

(ii) Adsorption

(iii) Shape selective catalysis

21. ×®Ö´®Ö ×¾Ö׬ֵÖÖë «üÖ¸üÖ ¬ÖÖŸÖã†Öë Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûêú †Ö¬ÖÖ¸ü ´Öæ»Ö ×ÃÖ¨üÖ®ŸÖ ×»Ö×ÜÖ‹ :

(i) †ÖÃÖ¾Ö®Ö

(ii) •ÖÖê®Ö ¯Ö׸üÂÛú¸üÞÖ

(iii) ¾ÖîªãŸÖ †¯Ö‘Ö™ü®Ö

†£Ö¾ÖÖ

†ÖµÖ¸ü®Ö Ûêú ×®ÖÂÛúÂÖÔÞÖ Ûêú ÃÖ´ÖµÖ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë •ÖÖê †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü ˆ®Æëü ×»Ö×ÜÖ‹ … œü»Ö¾Öë

»ÖÖêÆêü ÃÖê Ûú““ÖÖ (Pig) »ÖÖêÆüÖ ÛîúÃÖê ׳֮®Ö ÆüÖêŸÖÖ Æîü ?

Outline the principles of refining of metals by the following methods :

(i) Distillation

(ii) Zone refining

(iii) Electrolysis

OR

Write down the reactions taking place in different zones in the blast furnace during the

extraction of iron. How is pig iron different from cast iron ?

Page 65: Chemistry Past Papers

56/1/2 8

22. »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö ŒµÖÖ Æîü ? »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö Ûêú ŒµÖÖ ¯Ö׸üÞÖÖ´Ö ÆüÖêŸÖê Æïü ?

What is lanthanoid contraction ? What are the consequences of lanthanoid contraction ?

23. ¸ü´Öê¿Ö ‹Ûú ×›ü¯ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ÝÖµÖÖ ¾ÖÆüÖÑ ˆÃÖê Ûãú”û ‘Ö¸ü Ûêú ×»ÖµÖê ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®ÖÖ £ÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ˆÃÖ®Öê ¿ÖãÝÖ¸ü-

±Ïúß ×™ü×ÛúµÖÖÑ ¤êüÜÖß … ˆÃÖ®Öê ˆ®Æëü †¯Ö®Öê ¤üÖ¤üÖ Ûêú ×»ÖµÖê ÜÖ¸üߤü®Öê ÛúÖ ×®ÖÞÖÔµÖ ×ÛúµÖÖ •ÖÖê ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ŸÖß®Ö ¯ÖÏÛúÖ¸ü

Ûúß ¿ÖãÝÖ¸ü-±Ïúß ×™ü×ÛúµÖÖÑ ´ÖÖî•Öæ¤ü £Öà … ¸ü´Öê¿Ö ®Öê ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú þÖÖãµÖ Ûêú

×»ÖµÖê †“”ûß £Öà …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ±Ïúß ×™ü×ÛúµÖÖ ÛúÖ ˆ»»ÖêÜÖ Ûúßו֋ וÖÃÖê ¸ü´Öê¿Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ײ֮ÖÖ ›üÖòŒ™ü¸ü Ûúß ¯Ö“Öá Ûêú ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ŒµÖÖ ¸ü´Öê¿Ö Ûêú ×»Ö‹ ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ×¾Ö¾ÖÞÖÔ ÃÖê ¸ü´Öê¿Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖÖ Æîü ?

Ramesh went to a departmental store to purchase groceries. On one of shelves he

noticed sugar-free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar-free tablets. Ramesh decided to buy

sucrolose which was good for his grandfather’s health.

(i) Name another sugar free tablet which Ramesh did not buy.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Ramesh is reflected above ?

24. (a) ×®Ö´®Ö ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

(i) Cu + HNO3(ŸÖ®Öã) →

(ii) P4 + NaOH+ H2O →

(b) (i) ŒµÖÖë R3P = O ²Ö®ÖŸÖÖ Æîü ¯Ö¸ü®ŸÖã R3N = O ®ÖÆüà ²Ö®ÖŸÖÖ Æîü ? (R = ‹×»Ûú»Ö ÝÖÏã Ö)

(ii) ›üÖ‡†ÖòŒÃÖß•Ö®Ö ŒµÖÖë ‹Ûú ÝÖîÃÖ Æîü ¯Ö¸ü®ŸÖã ÃÖ»±ú¸ü ‹Ûú šüÖêÃÖ Æîü ?

(iii) Æîü»ÖÖê•Ö®Ö ŒµÖÖë ÓüÝÖµÖãŒŸÖ ÆüÖêŸÖê Æïü ?

†£Ö¾ÖÖ

Page 66: Chemistry Past Papers

56/1/2 9 [P.T.O.

(a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»Ö‹ ÃÖÓŸÖã×»ÖŸÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ : (i) ²Öã—Öê “Öæ®Öê Ûêú ÃÖÖ£Ö Œ»ÖÖê üß®Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü … (ii) ÛúÖ²ÖÔ®Ö ÃÖÖÓ¦ü H2SO4 ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü …

(b) ÃÖ»°µÖæ׸üÛú †´»Ö ÛúÖê ÛúÖÓ™îüŒ™ü ×¾Ö×¬Ö ÃÖê ²Ö®ÖÖ®Öê ÛúÖ ×®Ö´®Ö ÃÖÓ¤ü³ÖÖí, •ÖîÃÖê †×¬ÖÛúŸÖ´Ö ˆŸ¯ÖÖ¤ü, ˆŸ¯ÖÏê üÞÖ †Öî ü †®µÖ ×ãÖ×ŸÖ ´Öë ¾ÖÞÖÔ®Ö Ûúßו֋ …

(a) Complete the following chemical reaction equations :

(i) Cu + HNO3(dilute) →

(ii) P4 + NaOH+ H2O →

(b) (i) Why does R3P = O exist but R3N = O does not ? (R = alkyl group)

(ii) Why is dioxygen a gas but sulphur a solid ?

(iii) Why are halogens coloured ?

OR

(a) Write balanced equations for the following reactions :

(i) Chlorine reacts with dry slaked lime.

(ii) Carbon reacts with concentrated H2SO4.

(b) Describe the contact process for the manufacture of sulphuric acid with special

reference to the reaction conditions, catalysts used and the yield in the process.

25. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤êüŸÖê Æãü‹ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ›üßÛúÖ²ÖÖì׌ÃÖ»ÖßÛú¸üÞÖ †×³Ö×ÛÎúµÖÖ

(ii) ±ÏúÖ‡›êü»Ö-ÛÎîú°™ü †×³Ö×ÛÎúµÖÖ

(b) †Ö¯Ö ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ²ÖꮕÖÌÖê‡Ûú †´»Ö ÛúÖê ²ÖꮕÖî×»›üÆüÖ‡›ü ´Öë

(ii) ²ÖꮕÖÌß®Ö ÛúÖê m-®ÖÖ‡™ÒüÖê‹ÃÖß™üÖ±úß®ÖÖê®Ö ´Öë

(iii) ‹£Öî®ÖÖò»Ö ÛúÖê 3-ÆüÖ‡›ÒüÖòŒÃÖß ²µÖæ™îü®Öî»Ö ´Öë

†£Ö¾ÖÖ

Page 67: Chemistry Past Papers

56/1/2 10

(a) ×®Ö´®Ö ×ÛÎúµÖÖ†Öë ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ‹ÃÖß×™ü»ÖßÛú¸üÞÖ

(ii) ‹ê»›üÖê»Ö ÃÖÓ‘Ö®Ö®Ö

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ †×³Ö×ÛÎúµÖÖ†Öë Ûêú ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ÛúÖê ×»Ö×ÜÖ‹ :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

(a) Describe the following giving chemical equations :

(i) De-carboxylation reaction

(ii) Friedel-Crafts reaction

(b) How will you bring about the following conversions ?

(i) Benzoic acid to Benzaldehyde

(ii) Benzene to m-Nitroacetophenone

(iii) Ethanol to 3-Hydroxybutanal

OR

(a) Describe the following actions :

(i) Acetylation (ii) Aldol condensation

(b) Write the main product in the following equations :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

Page 68: Chemistry Past Papers

56/1/2 11 [P.T.O.

26. (a) ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ (^m)

(ii) ÃÖÓ“ÖÖµÖÛú ²Öî™ü׸üµÖÖÑ

(iii) ‡Õ¬Ö®Ö ÃÖê»Ö

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ ×®ÖµÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ :

(i) ±îú¸üÖ›êü Ûêú ¾ÖîªãŸÖ†¯Ö‘Ö™ü®Ö ÛúÖ ¯ÖÏ£Ö´Ö ×®ÖµÖ´Ö

(ii) ÛúÖê»Ö¸üÖ‰ú¿Ö Ûêú †ÖµÖ®ÖÖë Ûêú þ֟ÖÓ¡Ö †×³ÖÝÖ´Ö®Ö ÛúÖ ×®ÖµÖ´Ö

†£Ö¾ÖÖ

(a) ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ‹Ûú ¾µÖÓ•ÖÛú ×»Ö×ÜÖ‹ •ÖÖê ¤ãü²ÖÔ»Ö ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûúß ´ÖÖê»Ö¸ü

“ÖÖ»ÖÛúŸÖÖ ÛúÖê ‡ÃÖÛêú ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ÆüÖêŸÖÖ Æîü …

(b) ÃÖê»Ö †×³Ö×ÛÎúµÖÖ

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Ûêú ×»ÖµÖê 25 °C ¯Ö¸ü ŸÖã»µÖ ×ãָüÖÓÛú ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ … ‡ÃÖ ÃÖê»Ö Ûêú ÛúÖ´Ö Ûú¸ü®Öê ¯Ö¸ü †×¬ÖÛúŸÖ´Ö ×ÛúŸÖ®ÖÖ

ÛúÖµÖÔ ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü ?

E°Ni2+/Ni

= 0.25 V, E°Ag+/Ag

= 0.80 V.

(a) Define the following terms :

(i) Molar conductivity (^m)

(ii) Secondary batteries

(iii) Fuel cell

(b) State the following laws :

(i) Faraday first law of electrolysis

(ii) Kohlrausch’s law of independent migration of ions

OR

(a) Define the term degree of dissociation. Write an expression that relates the molar

conductivity of a weak electrolyte to its degree of dissociation.

(b) For the cell reaction

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Calculate the equilibrium constant at 25 °C. How much maximum work would

be obtained by operation of this cell ?

E°Ni2+/Ni

= 0.25 V and E°Ag+/Ag

= 0.80 V.

___________

Page 69: Chemistry Past Papers

56/1/2 12

Page 70: Chemistry Past Papers

1

Qu

es. Value points Marks

1 It is a process of removing a dissolved substance from a colloidal solution by means of diffusion

through a suitable membrane.

1

2 Hexaamninenickel (II) chloride 1

3

1

4

(where Ar is C6H5)

1

5 2 1

6 Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

OR

1

1

6 i) Due to presence of unpaired electrons in d-orbitals.

ii) Due to incomplete filling of d-orbitals.

1

1

7

½

½

1

8 The external pressure which is applied on solution side to stop the flow of solvent across the

semi-permeable membrane.

The osmotic pressure is directly proportional to concentration of the solution. / = CRT

1

1

CHEMISTRY MARKING SCHEME

SET -56/1/2

Compt. July, 2015

Page 71: Chemistry Past Papers

2

9 The half-life of a reaction is the time in which the concentration of a reactant is reduced to one-

half of its initial concentration.

Rate constant is the rate of reaction when the concentration of the reactant is unity.

1

1

10

i) ii)

1+1

11 a) Linkage isomerism

b) Optical isomerism

c) Cis - trans / Geometrical isomerism

1

1

1

12 a) Butan – 2 – ol

b) 2 – bromotoluene

c) 2, 2-dimethylchlorpropane

1

1

1

13 i)

ii)

iii)

1

1

1

14

A – Benzoic acid

B – Benzamide

C - Aniline

½ +

½

½ +

½

Page 72: Chemistry Past Papers

3

½ +

½

15 Fat soluble vitamin- Vitamin A, D

Water soluble vitamin-Vitamin B,C

Vitamin K

½+½

½+½

1

16 i)

ii)

iii)

½ +

½

½ +

½

½ +

½

17 i) The defect in which equal number of cations and anions are missing from the lattice.

ii) Due to dislocation of smaller ion from its normal site to an interstitial site.

iii) Anionic vacancies are occupied by unpaired electron.

1

1

1

18 i) ∆Tf = Kf m

∆Tf = Kf

∆Tf =

∆Tf =2.325K or 2.3250

C

ii) Tf0- Tf = 2.325

0 C

O0C - Tf = 2.325

0 C

Tf = - 2.3250

C or 270.675 K

½

½

1

1

19

1

1

1

20 i) The movement of colloidal particles under an applied electric potential towards oppositely

charged electrode is called electrophoresis.

ii) The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid

is termed adsorption.

iii) The catalytic reaction that depends upon the pore structure of the catalyst and the size of the

reactant and product molecules is called shape-selective catalysis.

1

1

1

Page 73: Chemistry Past Papers

4

21 i) The impure metal is evaporated to obtain the pure metal as distillate.

ii) This method is based on the principle that the impurities are more soluble in the melt than in

the solid state of the metal.

iii) The impure metal is made to act as anode. A strip of the same metal in pure form is used as

cathode. They are put in a suitable electrolytic bath containing soluble salt of the same metal.

The more basic metal remains in the solution and the less basic ones go to the anode mud.

OR

1

1

1

( any four correct equations) Cast iron has lower carbon content (about 3%) than pig iron / cast iron is hard & brittle whereas pig iron is soft.

½ x 4

= 2

1

22 The steady decrease in atomic radii from La to Lu due to imperfect shielding of 4f – orbital.

Consequences –

i) Members of third transition series have almost identical radii as coresponding members

of second transition series.

ii) Difficulty in separation.

1

1+1

23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2

24 a) i)

ii)

b) i) Due to absence of d-orbital, nitrogen cannot expand its valency beyond four.

ii) Because of pπ – pπ multiple bonding in dioxygen which is absent in sulphur.

iii) Due to excitation of electron by absorption of radiation from visible region. OR

1

1

1

1

1

a) i)

ii)

b) It is manufactured by Contact Process which involves following steps:

i) burning of sulphur or sulphide ores in air to generate SO2.

ii) conversion of SO2 to SO3 by the reaction with oxygen in the presence of a catalyst (V2O5)

iii) absorption of SO3 in H2SO4 to give Oleum (H2S2O7). The oleum obtained is diluted to give

sulphuric acid

Reaction condition – pressure of 2 bar and temperature of 720 K

Catalyst used is V2O5

1

1

1

1

1

Page 74: Chemistry Past Papers

5

Yield – 96 – 98% pure

25 a) i) Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are

heated with sodalime (NaOH and CaO).

ii) When the alkyl / acyl group is introduced at ortho and para positions by reaction

with alkyl halide / acyl halide in the presence of anhydrous aluminium chloride (a Lewis

acid) as catalyst.

(Note : Award full marks if correct equation is given )

b) i)

ii)

iii)

(or any other correct method)

OR

1

1

1

1

1

25 a) i) When the acyl groups are introduced at ortho and para positions by reaction with acyl halide in the

presence of anhydrous aluminium chloride (a Lewis acid) as catalyst.

ii) Aldehydes and ketones having at least one -hydrogen undergo a reaction in the presence of

dilute alkali as catalyst to form -hydroxy aldehydes (aldol) or hydroxy ketones (ketol),

respectively.

1

1

Page 75: Chemistry Past Papers

6

(Note : Award full marks if correct equation is given )

b)i)

ii)

iii) CH3COCl

1

1

1

26 a)i)Molar conductivity of a solution at a given concentration is the conductance of the volume V

of solution containing one mole of electrolyte kept between two electrodes with area of cross

section A and distance of unit length.

ii) Secondary battery- can be recharged by passing current through it in opposite direction so that

it can be used again.

iii) Galvanic cells that are designed to convert the energy of combustion of fuels like hydrogen,

methane, methanol, etc. directly into electrical energy are called fuel cells.

b)i) The amount of chemical reaction which occurs at any electrode during electrolysis by a

current is proportional to the quantity of electricity passed through the electrolyte (solution or

melt).

ii) Limiting molar conductivity of an electrolyte can be represented as the sum of the individual

contributions of the anion and cation of the electrolyte.

OR

1

1

1

1

1

26 a) Degree of dissociation is the extent to which electrolyte gets dissociated into its constituent

ions.

b) E

0cell = E

0Ag+ / Ag - E

0Ni2+ / Ni

= 0.80V – 0.25V

= 0.55V

1og Kc =

=

log Kc = 18.644

∆G0 = - nFE

0cell

= -2x96500 Cmol-1

x 0.55V

= -106,150 Jmol-1

Max.work =+106150 Jmol-1

or 106.150k Jmol-1

1

1

½

½

½

½

1

Page 76: Chemistry Past Papers

7

Dr. Sangeeta Bhatia Sh. S.K. Munjal Sh. D.A. Mishra

Ms. Garima Bhutani

Page 77: Chemistry Past Papers

56/1 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸ü ÃÖ Ö µÖ ®Ö × ¾Ö – Ö Ö ®Ö (ÃÖî ü Ö × ®ŸÖ Û ú ) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ŸÖÛú ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü †Öî ü ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛúŸÖÖ ÆüÖê, ŸÖÖê »ÖÖòÝÖ ™êü²Ö»ÖÖë ÛúÖ ¯ÖϵÖÖêÝÖ Ûú¸ëü … Ûîú»ÖÛãú»Öê™ü¸üÖë Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/C 56/1

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 12 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 1

Page 78: Chemistry Past Papers

56/1 2

General Instructions :

(i) All questions are compulsory.

(ii) Question number 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Question number 6 to 10 are short answer questions and carry 2 marks each.

(iv) Question number 11 to 22 are also short answer questions and carry 3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Question number 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. AgCl ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ Ã™üÖê‡×ÛúµÖÖê Öß™Òüß ¤üÖêÂÖ ¤ü¿ÖÖÔŸÖÖ Æîü ?

What type of stoichiometric defect is shown by AgCl ?

2. ‡´Ö»¿Ö®Ö ŒµÖÖ ÆüÖêŸÖê Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

What are emulsions ? Give an example.

3. ‘Ûúß»Öê™’ü ¯ÖϳÖÖ¾Ö ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

What is meant by chelate effect ?

4. ×®Ö´®Ö ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

CH3 – CH2 – CHO

Write the IUPAC name of the following :

CH3 – CH2 – CHO

5. ×®Ö´®Ö ÛúÖê õÖÖ¸üßµÖ õÖ´ÖŸÖÖ Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ¾µÖ¾Ö×Ã£ÖŸÖ Ûúßו֋ :

‹ê×®Ö»Öß®Ö, p-®ÖÖ‡™ÒüÖê‹ê×®Ö»Öß®Ö †Öî ü p-™üÖ»Ö㇛Ìüß®Ö

Arrange the following in increasing order of basic strength :

Aniline, p-Nitroaniline and p-Toluidine

Page 79: Chemistry Past Papers

56/1 3 [P.T.O.

6. ×®Ö´®Ö ¯Ö¤üÖë Ûúß ¯Ö׸ü³ÖÖÂÖÖ‹Ñ ×»Ö×ÜÖµÖê :

(i) ´ÖÖê»ÖÖÓ¿Ö (x)

(ii) ‹Ûú ×¾Ö»ÖµÖ®Ö Ûúß ´ÖÖê»Ö»ÖŸÖÖ (m)

Define the following terms :

(i) Mole fraction (x)

(ii) Molality of a solution (m)

7. •Ö߸üÖê †Öò›Ôü¸ü †Öî ü ׫üŸÖßµÖ †Öò›Ôü¸ü †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛúÖë Ûêú µÖæ×®Ö™ü ×»Ö×ÜÖ‹ ˆÃÖ ×ãÖ×ŸÖ ´Öë •Ö²Ö ÃÖÖÓ¦üŸÖÖ

ÛúÖê mol L–1 †Öî ü ÃÖ´ÖµÖ ÛúÖê ÃÖêÛúÞ›üÖë ´Öë ×»ÖÜÖÖ ÝÖµÖÖ ÆüÖê …

Write units of rate constants for zero order and for the second order reactions if the

concentration is expressed in mol L–1 and time in second.

8. ×®Ö´®Ö Ûú£Ö®ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ±úÖòñúÖê üÃÖ Ûúß †¯ÖêõÖÖ ®ÖÖ‡™ÒüÖê•Ö®Ö ²ÖÆãüŸÖ Ûú´Ö ÃÖ×ÛÎúµÖ Æîü …

(ii) NF3 ‹Ûú ‰ú´ÖÖõÖê Öß ¯Ö¤üÖ£ÖÔ Æîü ¯Ö¸ü®ŸÖã NCl3 ‰ú´ÖÖ¿ÖÖêÂÖß ¯Ö¤üÖ£ÖÔ Æîü …

Explain the following :

(i) Nitrogen is much less reactive than phosphorus.

(ii) NF3 is an exothermic compound but NCl3 is an endothermic compound.

9. ¯ÖÖê™îü×¿ÖµÖ´Ö ¯Ö¸ü´ÖïÝÖ®Öê™ü Ûúß ×®Ö´ÖÖÔÞÖ ×¾Ö×¬Ö ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ … †´»ÖßÛéúŸÖ ¯Ö¸ü´ÖîÓÝÖ®Öê™ü †ÖòŒÃÖî×»ÖÛú †´»Ö Ûêú ÃÖÖ£Ö ÛîúÃÖê

†×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ? †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ …

†£Ö¾ÖÖ

¯ÖÖê™îü×¿ÖµÖ´Ö ›üÖ‡ÛÎúÖê Öê™ü Ûúß †ÖòŒÃÖßÛú¸üÞÖ ×ÛÎúµÖÖ ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ †Öî ü ‡ÃÖÛúß (i) †ÖµÖÖê›üÖ‡›ü (ii) H2S Ûêú ÃÖÖ£Ö

ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»ÖµÖê †ÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ×»Ö×ÜÖ‹ …

Page 80: Chemistry Past Papers

56/1 4

Describe the preparation of potassium permanganate. How does the acidified

permanganate solution react with oxalic acid ? Write the ionic equations for the

reactions.

OR

Describe the oxidising action of potassium dichromate and write the ionic equations

for its reaction with (i) an iodide (ii) H2S.

10. ‹£Öî®ÖÖò»Ö ÃÖê ‹£Öß®Ö ²Ö®Ö®Öê ´Öë †´»Ö ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ×ÛÎúµÖÖ×¾Ö×¬Ö ×»Ö×ÜÖ‹ …

Write the mechanism of acid dehydration of ethanol to yield ethene.

11. ×ÃÖ»¾Ö¸ü fcc •ÖÖ»ÖÛú ´Öë ×ÛÎúÙü×»ÖŸÖ ÆüÖêŸÖÖ Æîü … µÖפü µÖæ×®Ö™ü ÃÖê»Ö Ûêú ÛúÖê ü Ûúß »Ö´²ÖÖ‡Ô 4.077 × 10–8 cm ÆüÖê, ŸÖÖê

×ÃÖ»¾Ö¸ü ÛúÖ †¬ÖÔ¾µÖÖÃÖ (r) ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

Silver crystallises in fcc lattice. If edge length of the unit cell is 4.077 × 10–8 cm, then

calculate the radius of silver atom.

12. Ûêú®Ö-¿ÖãÝÖ¸ü (M.W. 342) ÛúÖ 5 ¯ÖÏ×ŸÖ¿ÖŸÖ ‘ÖÖê»Ö (¦ü¾µÖ´ÖÖ®Ö †Ö¬ÖÖ¸ü ¯Ö¸ü) ‹Ûú ¯Ö¤üÖ£ÖÔ X Ûêú 0.877% ‘ÖÖê»Ö Ûêú ÃÖÖ£Ö

†Ö‡ÃÖÖê™üÖê×®ÖÛú Æîü … X ÛúÖ †ÖÞÖ×¾ÖÛú ³ÖÖ¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

A 5 percent solution (by mass) of cane-sugar (M.W. 342) is isotonic with 0.877%

solution of substance X. Find the molecular weight of X.

13. ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú ×»ÖµÖê ¤ü¸ü ×ãָüÖÓÛú 60 s–1 Æîü … †×³ÖÛúÖ¸üÛú Ûêú ¯ÖÏÖ¸ü×´³ÖÛú ÃÖÖÓ¦üÞÖ ÛúÖê ‡ÃÖÛêú 1/10

ŸÖÛú ‘Ö™®Öêê ´Öë ×ÛúŸÖ®ÖÖ ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ?

The rate constant for a first order reaction is 60 s–1. How much time will it take to

reduce the initial concentration of the reactant to its 1/10th

value ?

Page 81: Chemistry Past Papers

56/1 5 [P.T.O.

14. ×®Ö´®Ö ¯ÖÏÛÎú´ÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :

(i) ›üÖµÖ×»Ö×ÃÖÃÖ

(ii) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(iii) ×™üÞ›ü»Ö ¯ÖϳÖÖ¾Ö

Describe the following processes :

(i) Dialysis

(ii) Electrophoresis

(iii) Tyndall effect

15. ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ‹ê»Öã×´Ö×®ÖµÖ´Ö Ûêú ¬ÖÖŸÖãÛú´ÖÔ ´Öë ÛÎúÖ‡µÖÖê»ÖÖ‡™ü Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(ii) ³Ö•ÖÔ®Ö ×ÛÎúµÖÖ †Öî ü ×®ÖßÖÖ¯Ö®Ö ´Öë †ÓŸÖ¸ü Ûúßו֋ …

(iii) ‘ÛÎúÖê Öîê™üÖêÝÖÏî±úß’ ¯Ö¤ü ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ?

†£Ö¾ÖÖ

»ÖÖêÆüÖ ²Ö®ÖÖ®Öê Ûêú ×»Ö‹ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë ´Öë ÆüÖê®Öê ¾ÖÖ»Öß †×³Ö×ÛÎúµÖÖ‹Ñ ×»Ö×ÜÖ‹ …

Answer the following :

(i) What is the role of cryolite in the metallurgy of aluminium ?

(ii) Differentiate between roasting and calcination.

(iii) What is meant by the term ‘chromatography’ ?

OR

Write the reactions taking place in different zones of the blast furnace to obtain Iron.

16. ‘†®ÖÖ®Öã ÖÖŸÖ®Ö’ ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ ÆüÖêŸÖÖ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ‹Ûú ˆ¤üÖÆü üÞÖ ¤üßו֋ …

What is meant by ‘disproportionation’ ? Give one example of disproportionation

reaction in aqueous solutions.

Page 82: Chemistry Past Papers

56/1 6

17. ×®Ö´®Ö×»Ö×ÜÖŸÖ Ûêú IUPAC ®ÖÖ´Ö ×»Ö×ÜÖ‹ :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

Write the IUPAC name of the following :

(i) [Co(NH3)6]Cl3

(ii) [NiCl4]2–

(iii) K3[Fe(CN)6]

18. ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ¤üßו֋ :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

Give the IUPAC names of the following compounds :

(i) CH3 – CH –| Br

CH2 – CH3

(ii)

Br

Br

(iii) CH2 = CH – CH2 – Cl

Page 83: Chemistry Past Papers

56/1 7 [P.T.O.

19. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ²Öê×®•Ö»Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ²Öê×®•Ö»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë

(ii) ‹×£Ö»Ö ´ÖîÝ®Öß×¿ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖ ¯ÖÏÖê Öê®Ö-1-†Öò»Ö ´Öë

(iii) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë

How are the following conversions carried out ?

(i) Benzyl chloride to Benzyl alcohol

(ii) Ethyl magnesium chloride to Propan-1-ol

(iii) Propene to Propan-2-ol

20. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ×»Ö×ÜÖ‹ :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

Write the major product in the following equations :

(i) CH3 – CH2OH –––––––––→PCl

5 ?

(ii)

OH

+ CH3– Cl ––––––––––––––––––→anhyd. AlCl

3 ?

(iii) CH3 – Cl + CH3CH2 – ONa → ?

21. ¯ÖÏÖê™üß®Ö ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ×®Ö´®Ö ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¯Öê ™üÖ‡›ü Ø»ÖÛêú•Ö

(ii) ¯ÖÏÖ‡´Ö¸üß ÃÖÓ ü“Ö®ÖÖ

(iii) ›üß®Öî“Öã êü¿Ö®Ö

Define the following as related to proteins :

(i) Peptide linkage

(ii) Primary structure

(iii) Denaturation

Page 84: Chemistry Past Papers

56/1 8

22. ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ ¯Ö¤ü Ûúß ¾µÖÖܵÖÖ Ûúßו֋ †Öî ü ‘ÛúÖê ÖÖò»Öß´Ö¸üÖ‡•Öê¿Ö®Ö’ Ûêú ¤üÖê ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

Explain the term ‘copolymerization’ and give two examples of copolymerization.

23. ®Ö߸ü•Ö ×›ü ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ‘Ö¸ü Ûêú ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®Öê Ûêú ×»ÖµÖê ÝÖµÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ¾ÖÆü Ûãú”û ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ

¤êüÜÖÖ … ¾ÖÆü Ûãú”û ‹êÃÖß ×™ü×ÛúµÖÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß, ŒµÖÖë×Ûú ˆÃÖÛêú

¤üÖ¤üÖ ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ¾ÖÆüÖÑ ŸÖß®Ö ¯ÖÏÛúÖ¸ü Ûúß ¿ÖãÝÖ¸ü¸ü×ÆüŸÖ ×™ü×ÛúµÖÖÑ £ÖßÓ … ˆÃÖ®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ¾ÖÆü ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤêü

•ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú ×»ÖµÖê ˆ¯ÖµÖÖêÝÖß £Öß …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ¸ü×ÆüŸÖ ÛúÖ ®ÖÖ´Ö ¤üßו֋ •ÖÖê ®Ö߸ü•Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ŒµÖÖ ›üÖŒ™ü¸ü Ûêú ¯Ö“Öá Ûêú ײ֮ÖÖ ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ®Ö߸ü•Ö Ûêú ×»ÖµÖê ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ÃÖê ®Ö߸ü•Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖÏןֻÖ×õÖŸÖ ÆüÖêŸÖÖ Æîü ?

Neeraj went to the departmental store to purchase groceries. On one of the shelves he

noticed sugar free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar free tablets. He decided to buy sucrolose

which was good for his grandfather’s health.

(i) Name another sugar free tablet which Neeraj did not purchase.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Neeraj is reflected above ?

24. ∆rG° †Öî ü e.m.f.(E) ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ •ÖÖê 25 °C ¯Ö¸ü Ùïü›ü›Ôü ×ãÖ×ŸÖ ´Öë ×®Ö´®Ö ÃÖê»Ö ÃÖê ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

פüµÖÖ ÝÖµÖÖ : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

†Öî ü F = 96500 C mol–1

†£Ö¾ÖÖ

Page 85: Chemistry Past Papers

56/1 9 [P.T.O.

(a) ‹Ûú ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûêú ×¾Ö»ÖµÖ®Ö Ûêú ×»ÖµÖê “ÖÖ»ÖÛúŸÖÖ †Öî ü ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

ÃÖÖÓ¦üŸÖÖ Ûêú ÃÖÖ£Ö ˆ®ÖÛêú ¯Ö׸ü¾ÖŸÖÔ®Ö Ûúß ¾µÖÖܵÖÖ Ûúßו֋ …

(b) ˆÃÖ ÝÖî»Ö¾ÖÖò×®ÖÛú ÃÖê»Ö Ûêú Ùïü›ü›Ôü ÃÖê»Ö ×¾Ö³Ö¾Ö ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ וÖÃÖ´Öë ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÆüÖêŸÖß Æîü :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

†×³Ö×ÛÎúµÖÖ ÛúÖ ∆rG° †Öî ü ŸÖ㻵ÖÖÓÛúß ×ãָüÖÓÛú ÛúÖ ¯Ö׸üÛú»Ö®Ö ³Öß Ûúßו֋ …

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

Calculate ∆rG° and e.m.f. (E) that can be obtained from the following cell under the

standard conditions at 25 °C :

Zn(s) | Zn2+(aq) || Sn2+(aq) | Sn(s)

Given : E°Zn

2+/Zn

= – 0.76 V; E°Sn

2+/Sn

= – 0.14 V

and F = 96500 C mol–1.

OR

(a) Define conductivity and molar conductivity for the solution of an electrolyte.

Discuss their variation with concentration.

(b) Calculate the standard cell potential of the galvanic cell in which the following

reaction takes place :

Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)

Calculate the ∆rG° and equilibrium constant of the reaction also.

(E°Ag

+/Ag

= 0.80 V; E°Fe

3+/Fe

2+ = 0.77 V)

Page 86: Chemistry Past Papers

56/1 10

25. (a) ÝÖÏã Ö 16 Ûêú ŸÖ¢¾Ö ÃÖÖ¬ÖÖ¸üÞÖŸÖµÖÖ ¯ÖÏ£Ö´Ö †ÖµÖ®Ö®Ö ‹®£ÖÖß ŸÖŸÃÖ´²Ö®¬Öß †Ö¾ÖŸÖÔ ¾ÖÖ»Öê ÝÖÏã Ö 15 Ûêú ŸÖ¢¾ÖÖë Ûúß

ŸÖã»Ö®ÖÖ ´Öë Ûú´Ö ´ÖÖ®Ö ¤ü¿ÖÖÔŸÖê Æïü … ‹êÃÖÖ ŒµÖÖë Æîü ?

(b) ŒµÖÖ ÆüÖêŸÖÖ Æîü •Ö²Ö –

(i) ÃÖÖÓ¦ü H2SO4 ÛúÖê CaF2 ¯Ö¸ü ›üÖ»ÖÖ •ÖÖŸÖÖ Æîü ?

(ii) ÃÖ»±Ìú¸ü ›üÖ‡†ÖòŒÃÖÖ‡›ü “ÖÖ¸üÛúÖê»Ö Ûúß ˆ¯Ö×ãÖ×ŸÖ ´Öë Œ»ÖÖê üß®Ö ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü ?

(iii) †´ÖÖê×®ÖµÖ´Ö Œ»ÖÖê üÖ‡›ü ÛúÖê Ca(OH)2 Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ×ÛúµÖÖ •ÖÖŸÖÖ Æîü ?

†£Ö¾ÖÖ

(a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) BrF3

(ii) XeO3

(b) ×®Ö´®Ö ¯ÖÏ¿®ÖÖë Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) PH3Ûúß †¯ÖêõÖÖ NH3 ŒµÖÖë †×¬ÖÛú õÖÖ¸üßµÖ ÆüÖêŸÖÖ Æîü ?

(ii) Æîü»ÖÖê•Ö®Ö ¯ÖÏ²Ö»Ö †ÖòŒÃÖßÛúÖ¸üÛú ŒµÖÖë ÆüÖêŸÖê Æïü ?

(iii) XeOF4 Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

(a) Elements of Gr. 16 generally show lower value of first ionization enthalpy

compared to the corresponding periods of Gr. 15. Why ?

(b) What happens when

(i) concentrated H2SO4 is added to CaF2 ?

(ii) sulphur dioxide reacts with chlorine in the presence of charcoal ?

(iii) ammonium chloride is treated with Ca(OH)2 ?

OR

Page 87: Chemistry Past Papers

56/1 11 [P.T.O.

(a) Draw the structure of the following :

(i) BrF3

(ii) XeO3

(b) Answer the following :

(i) Why is NH3 more basic than PH3 ?

(ii) Why are halogens strong oxidising agents ?

(iii) Draw the structure of XeOF4.

26. (a) ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) p-´Öê×£Ö»Ö²Öï•Ö̋׻›üÆüÖ‡›ü

(ii) 4-´Öê×£Ö»Ö¯Öî®™ü-3-‡Ô®Ö-2-†Öò®Ö

(b) ×®Ö´®Ö µÖÖî×ÝÖÛú µÖãÝ´ÖÖë ´Öë †ÓŸÖ¸ü Ûú¸ü®Öê Ûêú ×»ÖµÖê ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“ÖÖë ÛúÖê ¤üßו֋ :

(i) ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü †Öî ü ‹×£Ö»Ö²ÖꮕÖÌÖê‹™ü …

(ii) ²ÖꮕÖî×»›üÆüÖ‡›ü †Öî ü ‹êÃÖß™üÖê±úß®ÖÖê®Ö

(iii) ±úß®ÖÖò»Ö †Öî ü ²ÖꮕÖÌÖê‡Ûú ‹ê×ÃÖ›ü

†£Ö¾ÖÖ

(a) ×®Ö´®Ö ¾µÖ㟯֮®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö¸êü×ÜÖŸÖ Ûúßו֋ :

(i) ¯ÖÏÖê Öê®ÖÖê®Ö †Öò׌ÃÖ´Ö

(ii) CH3CHO ÛúÖ ÃÖê ÖßÛúÖ²Öì•ÖÖê®Ö

(b) ‹£Öî®ÖÖò»Ö ÛúÖê †Ö¯Ö ×®Ö´®Ö µÖÖî×ÝÖÛúÖë ´Öë ÛîúÃÖê ºþ¯ÖÖÓŸÖ׸üŸÖ Ûú ëüÝÖê ? ÃÖ´Ö²Ö¨ü ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤üßו֋ …

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

Page 88: Chemistry Past Papers

56/1 12

(a) Draw the structures of the following :

(i) p-Methylbenzaldehyde

(ii) 4-Methylpent-3-en-2-one

(b) Give chemical tests to distinguish between the following pairs of compounds :

(i) Benzoic acid and Ethyl benzoate.

(ii) Benzaldehyde and Acetophenone.

(iii) Phenol and Benzoic acid.

OR

(a) Draw the structures of the following derivatives :

(i) Propanone oxime

(ii) Semicarbazone of CH3CHO

(b) How will you convert ethanal into the following compounds ? Give the chemical

equations involved.

(i) CH3 – CH3

(ii) CH3 – CH –|

OH

CH2 – CHO

(iii) CH3CH2OH

_________

Page 89: Chemistry Past Papers

1

Qu

es. Value points Marks

1 Frenkel defect 1

2 Emulsions are liquid – liquid colloidal systems.

For example – milk, cream (or any other one correct example)

½ + ½

3 Formation of stable complex by polydentate ligand. 1

4 Propanal 1

5 p-Nitroaniline < Aniline < p-Toluidine 1

6 i)

ii) Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the

solvent. Or

1

1

7 Zero order : mol L-1

s-1

Second order : L mol-1

s-1

1

1

8 i) Due to high bond dissociation enthalpy of N N

ii) Due to low bond dissociation enthalpy of F2 than Cl2 and strong bond formation

between N and F

1

1

9 Potassium permanganate is prepared by fusion of MnO2 with an alkali metal hydroxide and an

oxidising agent like KNO3. This produces the dark green K2MnO4 which disproportionates in a

neutral or acidic solution to give permanganate.

Oxalate ion or oxalic acid is oxidised at 333 K:

OR

1

1

9 i)

ii)

1

1

CHEMISTRY MARKING SCHEME

SET -56/1

Compt. July, 2015

Page 90: Chemistry Past Papers

2

10

½

½

1

11 r =

r=

r = 1.44 x cm

1

1

1

cane sugar = πXח 12

Therefore, ccane sugar = cX (where c is molar concentration)

=

=

MX =

gmol

-1

MX = 59.9 or 60 gmol-1

1

1

1

13 k=

log

60 s-1

=

log

t=

log 10

t=

s

t= 0.0384 s

1

1

1

14 i) It is a process of removing the dissolved substance from a colloidal solution by means

of diffusion through a semi - permeable membrane.

ii) The movement of colloidal particles under an applied electric potential towards

oppositely charged electrode is called electrophoresis.

1

1

Page 91: Chemistry Past Papers

3

iii) Colloidal particles scatter light in all directions in space. This scattering of light

illuminates the path of beam in the colloidal dispersion.

1 15 i) It lowers the melting point of alumina / acts as a solvent.

ii)

Roasting Calcination

Ore is heated in a regular supply of air Heating in a limited supply or

absence of air.

(Or with equation)

iii) It is a process of separation of different components of a mixture which are differently

adsorbed on a suitable adsorbent. OR

1

1

1

15

(any 6 correct equations)

6 x ½

= 3

16

Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

1 ½

1 ½

17 i) Hexaamminecobalt(III) chloride

ii) Tetrachlorido nickelate(II)

iii) Potassium hexacyanoferrate(III)

1

1

1

18 i) 2-bromobutane

ii) 1, 3-dibromobenzene

iii) 3-choloropropene

1

1

1

19

i)

ii)

1

1

Page 92: Chemistry Past Papers

4

1

20

i)

ii)

iii)

1

1

1

21 i) Peptide linkage – in proteins, -amino acids are connected to each other by peptide

bond or peptide linkage (-CONH- bond).

ii) Primary structure - each polypeptide in a protein molecule having amino acids which

are linked with each other in a specific sequence.

iii) Denaturation - When a protein is subjected to physical change like change in

temperature or chemical change like change in pH, protein loses its biological activity.

1

1

1

22 Copolymerisation is a polymerisation reaction in which a mixture of more than one monomeric

species is allowed to polymerise and form a copolymer.

(or any other correct example)

1

1

1

23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2

24 E0cell = E

0Sn2+ / Sn - E

0Zn2+ / Zn

= - 0.14V –(- 0.76V)

= 0.62V

∆rG0 = -n F E

0cell

= - 2 x 96500 C mol-1

x 0.62 V

= - 119660 J mol-1

1

1

1

1

Page 93: Chemistry Past Papers

5

Ecell = E0

cell -

log

Ecell = 0.62 -

log

OR

1

24 a) The conductivity of a solution at any given concentration is the conductance of one unit

volume of solution kept between two platinum electrodes with unit area of cross section

and at a distance of unit length.

Molar conductivity of a solution at a given concentration is the conductance of the volume

V of solution containing one mole of electrolyte kept between two electrodes with area of

cross section A and distance of unit length.

Molar conductivity increases with decrease in concentration.

b)E0cell = E

0C - E

0A

= 0.80V – 0.77V

= 0.03V

∆rG0 = -n F E

0cell

= - 1 x 96500 C mol-1

x 0.03 V

= - 2895 J mol-1

Log Kc=

Log Kc=

Log Kc= 0.508

½

½

1

½

½

1

½

½

25 a) Due to relatively stable half – filled p-orbitals of group 15 elements

b) i) CaF2 + H2SO4 CaSO4 + 2HF

ii)

iii)

OR

2

1

1

1

25 a) i)

ii)

b) i)Due to small size of nitrogen, the lone pair of electron on nitrogen is localized/ easily

1

1

1

Page 94: Chemistry Past Papers

6

available for donation.

ii)Because they need only one electron to attain stable/noble gas configuration.

iii)

1

1

26 a) i)

ii)

b) i)Add NaHCO3, benzoic acid will give brisk effervescence of CO2 whereas ethylbenzoate

will not.

ii)Add NaOH and I2, acetophonone forms yellow ppt of iodoform on heating whereas

benzaldehyde will not.

iii)Add neutral FeCl3, phenol gives violet colouration whereas benzoic acid does not. (or any other correct test)

OR

1

1

1

1

1

26 a) i)

ii)

b) i)

ii)

1

1

1

1

Page 95: Chemistry Past Papers

7

Dr. Sangeeta Bhatia Sh. S.K. Munjal Sh. D.A. Mishra

Ms. Garima Bhutani

iii)

1

Page 96: Chemistry Past Papers

56/1/1 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸ü ÃÖ Ö µÖ ®Ö × ¾Ö – Ö Ö ®Ö (ÃÖî ü Ö × ®ŸÖ Û ú ) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÓ™êü ] [ †×¬ÖÛúŸÖ´Ö †ÓÛú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µ Ö ×®Ö¤ìü¿Ö ::::

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïüü …

(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú »ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1/C 56/1/1

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 11 Æïü … • ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë … • Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü … • Ûéú¯Öµ ÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢ Ö¸ü ×»ÖÜÖ®ÖÖ ¿Ö ãºþ Ûú¸ü®Öê ÃÖ ê ¯ÖÆü»Ö ê, ¯Ö Ï¿®Ö ÛúÖ ÛÎú ´ÖÖÓÛú †¾Ö¿µ Ö ×»ÖÜÖë … • ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê

×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 11 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the

question paper only and will not write any answer on the answer-book during this period.

ÛúÖê› ü ®ÖÓ. Code No.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 1

Page 97: Chemistry Past Papers

56/1/1 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. No. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. No. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. No. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. No. 23 is a value based question and carry 4 marks.

(vi) Q. No. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculator is not allowed.

1. ‹Ûú †ÓŸÖ: Ûêú×®¦üŸÖ ‘Ö®ÖßµÖ ÃÖÓ ü“Ö®ÖÖ ´Öë ¯Ö¸ü´ÖÖÞÖã†Öë Ûúß ÃÖÓܵÖÖ ¯ÖÏ×ŸÖ ‹ÛúÛú ÛúÖêךüÛúÖ (z) ŒµÖÖ ÆüÖêŸÖß Æîü ?

What is the no. of atoms per unit cell (z) in a body-centred cubic structure ?

2. ÃÖŸÖÆü ¸üÃÖÖµÖ®Ö Ûêú ÃÖÓ¤ü³ÖÔ ´Öë ›üÖµÖÖ×»Ö×ÃÖÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ …

In reference to surface chemistry, define dialysis.

3. ÛúÖò ¯»ÖêŒÃÖ [Ni(NH3)6]Cl2 ÛúÖ †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ×»Ö×ÜÖ‹ …

What is the IUPAC name of the complex [Ni(NH3)6]Cl2 ?

4. ×®Ö´®Ö µÖÖî×ÝÖÛú Ûúß ÃÖÓ ü“Ö®ÖÖ †Ö êü×ÜÖŸÖ Ûúßו֋ …

3-´Öê×£Ö»Ö¯Öê®™îü®Öî»Ö

Draw the structure of 3-methylpentanal.

5. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

Complete the following reaction equation :

C6H5N2Cl + H3PO2 + H2O ––––→ - - -

Page 98: Chemistry Past Papers

56/1/1 3 [P.T.O.

6. ×¾Ö»ÖµÖ®Ö Ûêú ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛúÖê ¯Ö× ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾Ö»ÖµÖ®Ö ´Öë ×¾Ö»ÖêµÖ Ûêú ÃÖÖÓ¦üÞÖ ÃÖê ¯Ö üÖÃÖ üÞÖß ¤üÖ²Ö ÛîúÃÖê ÃÖÓ²Ö×®¬ÖŸÖ Æîü ?

Define osmotic pressure of a solution. How is the osmotic pressure related to the

concentration of a solute in a solution ?

7. ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) †×³Ö×ÛÎúµÖÖ Ûúß †¬ÖÖÔµÖã (t½)

(ii) ¾ÖêÝÖ ×ãָüÖÓÛú (k)

Define the following terms :

(i) Half-life of a reaction (t½)

(ii) Rate constant (k)

8. ×®Ö´®ÖÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) H2SO4

(ii) XeF2

Draw the structures of the following :

(i) H2SO4

(ii) XeF2

9. ‘†ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö’ ÛúÖ ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë †ÃÖ´ÖÖ®ÖÖ®Öã ÖÖŸÖ®Ö †×³Ö×ÛÎúµÖÖ ÛúÖ ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

†£Ö¾ÖÖ

ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã ¸üÃÖÖµÖ®Ö Ûêú ×®Ö´®Ö »ÖõÖÞÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ÃÖã—ÖÖ‡‹ :

(i) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ †Öî ü ˆ®ÖÛêú µÖÖî×ÝÖÛú ÃÖÖ´ÖÖ®µÖŸÖÖ †®Öã“Öã ²ÖÛúßµÖ ÆüÖêŸÖê Æïü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¯Ö׸ü¾ÖŸÖÔ®Ö¿Öᯙ ˆ¯Ö“ÖµÖ®Ö †¾ÖãÖÖ‹Ñ ¯ÖϤüÙ¿ÖŸÖ Ûú¸üŸÖß Æïü …

What is meant by ‘disproportionation’ ? Give an example of a disproportionation

reaction in aqueous solution.

OR

Suggest reasons for the following features of transition metal chemistry :

(i) The transition metals and their compounds are usually paramagnetic.

(ii) The transition metals exhibit variable oxidation states.

Page 99: Chemistry Past Papers

56/1/1 4

10. ‹£Öî®ÖÖò»Ö Ûêú ×®Ö•ÖÔ»ÖßÛú¸üÞÖ Ûúß ¯ÖÏ×ÛÎúµÖÖ Ûêú “Ö¸üÞÖÖë Ûúß ¾µÖÖܵÖÖ Ûúßו֋ :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

Explain the mechanism of dehydration steps of ethanol :-

CH3CH2OH H+

→443 K

CH2 = CH2 + H2O

11. ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ¿ÖÖò™üÛúß ¤üÖêÂÖ

(ii) ±ÏëúÛêú»Ö ¤üÖêÂÖ

(iii) F-Ûëú¦ü

Define the following :

(i) Schottky defect

(ii) Frenkel defect

(iii) F-centre

12. ‹×£Ö»Öß®Ö Ý»ÖÖ‡ÛúÖê»Ö (C2H4O2) ÛúÖ 45 g •Ö»Ö Ûêú 600 g Ûêú ÃÖÖ£Ö ×´Ö»ÖÖµÖÖ ÝÖµÖÖ Æîü … ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(i) ×Æü´ÖÖÓÛú ÛúÖ †¾Ö®Ö´Ö®Ö †Öî ü

(ii) ×¾Ö»ÖµÖ®Ö ÛúÖ ×Æü´ÖÖÓÛú

(פüµÖÖ ÝÖµÖÖ Æîü : Kf ÛúÖ ´ÖÖ®Ö ¯ÖÖ®Öß Ûêú ×»Ö‹ = 1.86 K kg mol–1)

45 g of ethylene glycol (C2H4O2) is mixed with 600 g of water. Calculate

(i) the freezing point depression and

(ii) the freezing point of the solution

(Given : Kf of water = 1.86 K kg mol–1)

13. 500 K †Öî ü 700 K ¯Ö¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÛúÖ ¤ü¸ü ×ãָüÖÓÛú ÛÎú´Ö¿Ö: 0.02 s–1 †Öî ü 0.07 s–1 Æîü … ÃÖ×ÛÎúµÖÞÖ

‰ú•ÖÖÔ, Ea ÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ … (R = 8.314 J K–1 mol–1)

The rate constants of a reaction at 500 K and 700 K are 0.02 s–1 and 0.07 s–1

respectively. Calculate the value of activation energy, Ea. (R = 8.314 J K–1 mol–1)

Page 100: Chemistry Past Papers

56/1/1 5 [P.T.O.

14. ×®Ö´®Ö ¯Ö¤üÖë ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ‡»ÖꌙÒüÖê±úÖê êü×ÃÖÃÖ

(ii) †×¬Ö¿ÖÖêÂÖÞÖ

(iii) ¿Öê Ö-ÃÖê»Öê׌™ü¾Ö (†ÖÛéú×ŸÖ †Ö¬ÖÖ׸üŸÖ) ˆŸ¯ÖÏê üÞÖ

Define the following terms :

(i) Electrophoresis

(ii) Adsorption

(iii) Shape selective catalysis

15. ×®Ö´®Ö ×¾Ö׬ֵÖÖë «üÖ¸üÖ ¬ÖÖŸÖã†Öë Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûêú †Ö¬ÖÖ¸ü ´Öæ»Ö ×ÃÖ¨üÖ®ŸÖ ×»Ö×ÜÖ‹ :

(i) †ÖÃÖ¾Ö®Ö

(ii) •ÖÖê®Ö ¯Ö׸üÂÛú¸üÞÖ

(iii) ¾ÖîªãŸÖ †¯Ö‘Ö™ü®Ö

†£Ö¾ÖÖ

†ÖµÖ¸ü®Ö Ûêú ×®ÖÂÛúÂÖÔÞÖ Ûêú ÃÖ´ÖµÖ ²»ÖÖÙü ±ú®ÖìÃÖ Ûêú ×¾Ö׳֮®Ö ³ÖÖÝÖÖë •ÖÖê †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü ˆ®Æëü ×»Ö×ÜÖ‹ … œü»Ö¾Öë

»ÖÖêÆêü ÃÖê Ûú““ÖÖ (Pig) »ÖÖêÆüÖ ÛîúÃÖê ׳֮®Ö ÆüÖêŸÖÖ Æîü ?

Outline the principles of refining of metals by the following methods :

(i) Distillation

(ii) Zone refining

(iii) Electrolysis

OR

Write down the reactions taking place in different zones in the blast furnace during the

extraction of iron. How is pig iron different from cast iron ?

16. »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö ŒµÖÖ Æîü ? »ÖÖê®ÖÖòµÖ›ü ÃÖÓÛãú“Ö®Ö Ûêú ŒµÖÖ ¯Ö׸üÞÖÖ´Ö ÆüÖêŸÖê Æïü ?

What is lanthanoid contraction ? What are the consequences of lanthanoid contraction ?

Page 101: Chemistry Past Papers

56/1/1 6

17. ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖÖë «üÖ¸üÖ •ÖÖê ÃÖ´ÖÖ¾ÖµÖ¾ÖŸÖÖ Ûêú ¯ÖÏÛúÖ¸ü ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖê Æïü ˆ®ÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ‹×£Ö»Öß®Ö ›üÖ‡‹ê Öß®Ö)

(iii) [Pt(NH3)2Cl2]

Indicate the types of isomerism exhibited by the following complexes :

(i) [Co(NH3)5(NO2)]2+

(ii) [Co(en)3]Cl3 (en = ethylene diamine)

(iii) [Pt(NH3)2Cl2]

18. ×®Ö´®Ö Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´Ö ¤üßו֋ :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

Name the following according to IUPAC system :

(i) CH3 – CH –| OH

CH2 – CH3

(ii)

(iii) CH3

CH3|

– C –|

CH3

CH2 – Cl

Page 102: Chemistry Past Papers

56/1/1 7 [P.T.O.

19. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê ×ÛúµÖê •ÖÖŸÖê Æïü ?

(i) ¯ÖÏÖê Öß®Ö ÛúÖê ¯ÖÏÖê Öê®Ö-2-†Öò»Ö ´Öë …

(ii) ²Öê×®•ÖÌ»Ö Œ»ÖÖê üÖ‡›ü ÛúÖê ²Öê×®•ÖÌ»Ö ‹ê»ÛúÖêÆüÖò»Ö ´Öë …

(iii) ‹ê×®ÖÃÖÖê»Ö ÛúÖê p-²ÖÎÖê ÖÖê‹ê×®ÖÃÖÖê»Ö ´Öë …

How are the following conversions carried out ?

(i) Propene to propane-2-ol

(ii) Benzyl chloride to Benzyl alcohol

(iii) Anisole to p-Bromoanisole

20. ‹Ûú ‹ê üÖê Öî×™üÛú µÖÖî×ÝÖÛú ‘A’ •Ö»ÖßµÖ †´ÖÖê×®ÖµÖÖ Ûêú ÃÖÖ£Ö ˆ¯Ö“ÖÖ׸üŸÖ ÆüÖê®Öê †Öî ü ÝÖ´ÖÔ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘B’ ²Ö®ÖÖŸÖÖ Æîü

•ÖÖê Br2 †Öî ü KOH Ûêú ÃÖÖ£Ö ŸÖÖ×¯ÖŸÖ Ûú¸ü®Öê ¯Ö¸ü µÖÖî×ÝÖÛú ‘C’ ²Ö®ÖÖŸÖÖ Æîü … ‘C’ ÛúÖ †ÖÞÖ×¾ÖÛú ÃÖæ¡Ö C6H7N Æîü …

A, B †Öî ü C µÖÖî×ÝÖÛúÖë Ûêú †Ö‡Ô µÖæ ¯Öß ‹ ÃÖß (IUPAC) ®ÖÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ

Ûúßו֋ …

An aromatic compound ‘A’ on treatment with aqueous ammonia and heating forms

compound ‘B’ which on heating with Br2 and KOH forms a compound ‘C’ of

molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B

and C.

21. ×¾Ö™üÖ×´Ö®Öë ÛîúÃÖê ¾ÖÝÖáÛéúŸÖ Ûúß •ÖÖŸÖß Æïü ? ¸üŒŸÖ Ûêú ÃÛÓú¤ü®Ö Ûêú •ÖÖê ×¾Ö™üÖ×´Ö®Ö ˆ¢Ö¸ü¤üÖµÖß ÆüÖêŸÖê Æïü ˆ®ÖÛêú ®ÖÖ´Ö ¤üßו֋ …

How are vitamins classified ? Name the vitamin responsible for the coagulation of

blood.

22. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö †Öî ü ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) ²Öæ®ÖÖ-S

(ii) ®Ö߆Öê ÖÏß®Ö

(iii) ™êü°»ÖÖò®Ö

Write the names and structures of the monomers of the following polymers :

(i) Buna-S

(ii) Neoprene

(iii) Teflon

Page 103: Chemistry Past Papers

56/1/1 8

23. ¸ü´Öê¿Ö ‹Ûú ×›ü¯ÖÖ™Ôü´Öê®™ü»Ö ÙüÖê ü ´Öë ÝÖµÖÖ ¾ÖÆüÖÑ ˆÃÖê Ûãú”û ‘Ö¸ü Ûêú ×»ÖµÖê ÃÖÖ´ÖÖ®Ö ÜÖ¸üߤü®ÖÖ £ÖÖ … ‹Ûú ÜÖÖ®Öê ´Öë ˆÃÖ®Öê ¿ÖãÝÖ¸ü-

±Ïúß ×™ü×ÛúµÖÖÑ ¤êüÜÖß … ˆÃÖ®Öê ˆ®Æëü †¯Ö®Öê ¤üÖ¤üÖ Ûêú ×»ÖµÖê ÜÖ¸üߤü®Öê ÛúÖ ×®ÖÞÖÔµÖ ×ÛúµÖÖ •ÖÖê ¿ÖãÝÖ¸ü Ûêú ´Ö¸üß•Ö £Öê … ŸÖß®Ö ¯ÖÏÛúÖ¸ü

Ûúß ¿ÖãÝÖ¸ü-±Ïúß ×™ü×ÛúµÖÖÑ ´ÖÖî•Öæ¤ü £Öà … ¸ü´Öê¿Ö ®Öê ÃÖãÛÎúÖê»ÖÖêÃÖ ÜÖ¸üߤü®Öê ÛúÖ ×®Ö¿“ÖµÖ ×ÛúµÖÖ •ÖÖê ˆÃÖÛêú ¤üÖ¤üÖ Ûêú þÖÖãµÖ Ûêú

×»ÖµÖê †“”ûß £Öà …

(i) ‹Ûú †®µÖ ¿ÖãÝÖ¸ü ±Ïúß ×™ü×ÛúµÖÖ ÛúÖ ˆ»»ÖêÜÖ Ûúßו֋ וÖÃÖê ¸ü´Öê¿Ö ®Öê ®ÖÆüà ÜÖ¸üߤüÖ …

(ii) ײ֮ÖÖ ›üÖòŒ™ü¸ü Ûúß ¯Ö“Öá Ûêú ‹êÃÖß ¤ü¾ÖÖ ÜÖ¸üߤü®ÖÖ ŒµÖÖ ¸ü´Öê¿Ö Ûêú ×»Ö‹ ˆ×“ÖŸÖ £ÖÖ ?

(iii) ˆ¯Ö¸üÖêŒŸÖ ×¾Ö¾ÖÞÖÔ ÃÖê ¸ü´Öê¿Ö ÛúÖ ÛúÖî®Ö ÃÖÖ ÝÖãÞÖ ¯ÖϤüÙ¿ÖŸÖ ÆüÖêŸÖÖ Æîü ?

Ramesh went to a departmental store to purchase groceries. On one of shelves he

noticed sugar-free tablets. He decided to buy them for his grandfather who was a

diabetic. There were three types of sugar-free tablets. Ramesh decided to buy

sucrolose which was good for his grandfather’s health.

(i) Name another sugar free tablet which Ramesh did not buy.

(ii) Was it right to purchase such medicines without doctor’s prescription ?

(iii) What quality of Ramesh is reflected above ?

24. (a) ×®Ö´®Ö×»Ö×ÜÖŸÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ :

(i) ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ (^m)

(ii) ÃÖÓ“ÖÖµÖÛú ²Öî™ü׸üµÖÖÑ

(iii) ‡Õ¬Ö®Ö ÃÖê»Ö

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ ×®ÖµÖ´ÖÖë ÛúÖê ×»Ö×ÜÖ‹ :

(i) ±îú¸üÖ›êü Ûêú ¾ÖîªãŸÖ†¯Ö‘Ö™ü®Ö ÛúÖ ¯ÖÏ£Ö´Ö ×®ÖµÖ´Ö

(ii) ÛúÖê»Ö¸üÖ‰ú¿Ö Ûêú †ÖµÖ®ÖÖë Ûêú þ֟ÖÓ¡Ö †×³ÖÝÖ´Ö®Ö ÛúÖ ×®ÖµÖ´Ö

†£Ö¾ÖÖ

(a) ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ‹Ûú ¾µÖÓ•ÖÛú ×»Ö×ÜÖ‹ •ÖÖê ¤ãü²ÖÔ»Ö ×¾ÖªãŸÖË-†¯Ö‘Ö™ü¶ Ûúß ´ÖÖê»Ö¸ü

“ÖÖ»ÖÛúŸÖÖ ÛúÖê ‡ÃÖÛêú ×¾ÖµÖÖê•Ö®Ö Ûúß ×›üÝÖÏß ÃÖê ÃÖÓ²Ö×®¬ÖŸÖ ÆüÖêŸÖÖ Æîü …

(b) ÃÖê»Ö †×³Ö×ÛÎúµÖÖ

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Ûêú ×»ÖµÖê 25 °C ¯Ö¸ü ŸÖã»µÖ ×ãָüÖÓÛú ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ … ‡ÃÖ ÃÖê»Ö Ûêú ÛúÖ´Ö Ûú¸ü®Öê ¯Ö¸ü †×¬ÖÛúŸÖ´Ö ×ÛúŸÖ®ÖÖ

ÛúÖµÖÔ ¯ÖÏÖ¯ŸÖ ÆüÖêŸÖÖ Æîü ?

E°Ni2+/Ni

= 0.25 V, E°Ag+/Ag

= 0.80 V.

Page 104: Chemistry Past Papers

56/1/1 9 [P.T.O.

(a) Define the following terms :

(i) Molar conductivity (^m)

(ii) Secondary batteries

(iii) Fuel cell

(b) State the following laws :

(i) Faraday first law of electrolysis

(ii) Kohlrausch’s law of independent migration of ions

OR

(a) Define the term degree of dissociation. Write an expression that relates the molar

conductivity of a weak electrolyte to its degree of dissociation.

(b) For the cell reaction

Ni(s) | Ni2+(aq) || Ag+

(aq) | Ag(s)

Calculate the equilibrium constant at 25 °C. How much maximum work would

be obtained by operation of this cell ?

E°Ni2+/Ni

= 0.25 V and E°Ag+/Ag

= 0.80 V.

25. (a) ×®Ö´®Ö ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ :

(i) Cu + HNO3(ŸÖ®Öã) →

(ii) P4 + NaOH+ H2O →

(b) (i) ŒµÖÖë R3P = O ²Ö®ÖŸÖÖ Æîü ¯Ö¸ü®ŸÖã R3N = O ®ÖÆüà ²Ö®ÖŸÖÖ Æîü ? (R = ‹×»Ûú»Ö ÝÖÏã Ö)

(ii) ›üÖ‡†ÖòŒÃÖß•Ö®Ö ŒµÖÖë ‹Ûú ÝÖîÃÖ Æîü ¯Ö¸ü®ŸÖã ÃÖ»±ú¸ü ‹Ûú šüÖêÃÖ Æîü ?

(iii) Æîü»ÖÖê•Ö®Ö ŒµÖÖë ÓüÝÖµÖãŒŸÖ ÆüÖêŸÖê Æïü ?

†£Ö¾ÖÖ

(a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ×»Ö‹ ÃÖÓŸÖã×»ÖŸÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖ ×»Ö×ÜÖ‹ :

(i) ²Öã—Öê “Öæ®Öê Ûêú ÃÖÖ£Ö Œ»ÖÖê üß®Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖß Æîü …

(ii) ÛúÖ²ÖÔ®Ö ÃÖÖÓ¦ü H2SO4 ÃÖê †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü …

(b) ÃÖ»°µÖæ׸üÛú †´»Ö ÛúÖê ÛúÖÓ™îüŒ™ü ×¾Ö×¬Ö ÃÖê ²Ö®ÖÖ®Öê ÛúÖ ×®Ö´®Ö ÃÖÓ¤ü³ÖÖí, •ÖîÃÖê †×¬ÖÛúŸÖ´Ö ˆŸ¯ÖÖ¤ü, ˆŸ¯ÖÏê üÞÖ †Öî ü †®µÖ ×ãÖ×ŸÖ ´Öë ¾ÖÞÖÔ®Ö Ûúßו֋ …

Page 105: Chemistry Past Papers

56/1/1 10

(a) Complete the following chemical reaction equations :

(i) Cu + HNO3(dilute) →

(ii) P4 + NaOH+ H2O →

(b) (i) Why does R3P = O exist but R3N = O does not ? (R = alkyl group)

(ii) Why is dioxygen a gas but sulphur a solid ?

(iii) Why are halogens coloured ?

OR

(a) Write balanced equations for the following reactions :

(i) Chlorine reacts with dry slaked lime.

(ii) Carbon reacts with concentrated H2SO4.

(b) Describe the contact process for the manufacture of sulphuric acid with special

reference to the reaction conditions, catalysts used and the yield in the process.

26. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ÛúÖ ¸üÖÃÖÖµÖ×®ÖÛú ÃÖ´ÖßÛú¸üÞÖÖë ÛúÖê ¤êüŸÖê Æãü‹ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ›üßÛúÖ²ÖÖì׌ÃÖ»ÖßÛú¸üÞÖ †×³Ö×ÛÎúµÖÖ

(ii) ±ÏúÖ‡›êü»Ö-ÛÎîú°™ü †×³Ö×ÛÎúµÖÖ

(b) †Ö¯Ö ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ²ÖꮕÖÌÖê‡Ûú †´»Ö ÛúÖê ²ÖꮕÖî×»›üÆüÖ‡›ü ´Öë

(ii) ²ÖꮕÖÌß®Ö ÛúÖê m-®ÖÖ‡™ÒüÖê‹ÃÖß™üÖ±úß®ÖÖê®Ö ´Öë

(iii) ‹£Öî®ÖÖò»Ö ÛúÖê 3-ÆüÖ‡›ÒüÖòŒÃÖß ²µÖæ™îü®Öî»Ö ´Öë

†£Ö¾ÖÖ

(a) ×®Ö´®Ö ×ÛÎúµÖÖ†Öë ÛúÖ ¾ÖÞÖÔ®Ö Ûúßו֋ :

(i) ‹ÃÖß×™ü»ÖßÛú¸üÞÖ

(ii) ‹ê»›üÖê»Ö ÃÖÓ‘Ö®Ö®Ö

Page 106: Chemistry Past Papers

56/1/1 11 [P.T.O.

(b) ×®Ö´®Ö×»Ö×ÜÖŸÖ †×³Ö×ÛÎúµÖÖ†Öë Ûêú ´ÖãÜµÖ ˆŸ¯ÖÖ¤ü ÛúÖê ×»Ö×ÜÖ‹ :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

(a) Describe the following giving chemical equations :

(i) De-carboxylation reaction

(ii) Friedel-Crafts reaction

(b) How will you bring about the following conversions ?

(i) Benzoic acid to Benzaldehyde

(ii) Benzene to m-Nitroacetophenone

(iii) Ethanol to 3-Hydroxybutanal

OR

(a) Describe the following actions :

(i) Acetylation (ii) Aldol condensation

(b) Write the main product in the following equations :

(i) CH3 – C –| |O

CH3 –––––––––––––→LiAlH

4 ?

(ii)

CHO

–––––––––––––––––––→HNO

3 / H

2SO

4

273 – 283 K

?

(iii) CH3 – COOH –––––––––––––→PCl

5 ?

___________

Page 107: Chemistry Past Papers

56/1/1 12

Page 108: Chemistry Past Papers

1

Qu

es. Value points Marks

1 2 1

2 It is a process of removing a dissolved substance from a colloidal solution by means of diffusion

through a suitable membrane.

1

3 Hexaamninenickel (II) chloride 1

4

1

5

(where Ar is C6H5)

1

6. The external pressure which is applied on solution side to stop the flow of solvent across the

semi-permeable membrane.

The osmotic pressure is directly proportional to concentration of the solution. / = CRT

1

1

7. The half-life of a reaction is the time in which the concentration of a reactant is reduced to one-

half of its initial concentration.

Rate constant is the rate of reaction when the concentration of the reactant is unity.

1

1

8.

i) ii)

1+1

9

Disproportionation : The reaction in which an element undergoes self-oxidation and self-

reduction simultaneously. For example –

2Cu+ (aq) Cu

2+ (aq) + Cu(s)

(Or any other correct equation)

OR

1

1

9 i) Due to presence of unpaired electrons in d-orbitals.

ii) Due to incomplete filling of d-orbitals.

1

1

10

½

CHEMISTRY MARKING SCHEME

SET -56/1/1

Page 109: Chemistry Past Papers

2

½

1

11 i) The defect in which equal number of cations and anions are missing from the lattice.

ii) Due to dislocation of smaller ion from its normal site to an interstitial site.

iii) Anionic vacancies are occupied by unpaired electron.

1

1

1

12 i) ∆Tf = Kf m

∆Tf = Kf

∆Tf =

∆Tf =2.325K or 2.3250

C

ii) Tf0- Tf = 2.325

0 C

O0C - Tf = 2.325

0 C

Tf = - 2.3250

C or 270.675 K

½

½

1

1

13

1

1

1

14 i) The movement of colloidal particles under an applied electric potential towards oppositely

charged electrode is called electrophoresis.

ii) The accumulation of molecular species at the surface rather than in the bulk of a solid or liquid

is termed adsorption.

iii) The catalytic reaction that depends upon the pore structure of the catalyst and the size of the

reactant and product molecules is called shape-selective catalysis.

1

1

1

15 i) The impure metal is evaporated to obtain the pure metal as distillate.

ii) This method is based on the principle that the impurities are more soluble in the melt than in

the solid state of the metal.

iii) The impure metal is made to act as anode. A strip of the same metal in pure form is used as

cathode. They are put in a suitable electrolytic bath containing soluble salt of the same metal.

The more basic metal remains in the solution and the less basic ones go to the anode mud.

OR

1

1

1

Page 110: Chemistry Past Papers

3

15

( any four correct equations) Cast iron has lower carbon content (about 3%) than pig iron / cast iron is hard & brittle whereas pig iron is soft.

½ x 4

= 2

1

16 The steady decrease in atomic radii from La to Lu due to imperfect shielding of 4f – orbital.

Consequences –

i) Members of third transition series have almost identical radii as coresponding members

of second transition series.

ii) Difficulty in separation.

1

1+1

17 a) Linkage isomerism

b) Optical isomerism

c) Cis - trans / Geometrical isomerism

1

1

1

18 a) Butan – 2 – ol

b) 2 – bromotoluene

c) 2, 2-dimethylchlorpropane

1

1

1

19 i)

ii)

iii)

1

1

1

20

A – Benzoic acid

½ +

½

Page 111: Chemistry Past Papers

4

B – Benzamide

C - Aniline

½ +

½

½ +

½

21 Fat soluble vitamin- Vitamin A, D

Water soluble vitamin-Vitamin B,C

Vitamin K

½+½

½+½

1

22 i)

ii)

iii)

½ +

½

½ +

½

½ +

½

23 i) Aspartame, Saccharin (any one)

ii) No

iii) Social concern, empathy, concern, social awareness (any 2 )

1

1

2

24 a)i)Molar conductivity of a solution at a given concentration is the conductance of the volume V

of solution containing one mole of electrolyte kept between two electrodes with area of cross

section A and distance of unit length.

ii) Secondary battery- can be recharged by passing current through it in opposite direction so that

it can be used again.

iii) Galvanic cells that are designed to convert the energy of combustion of fuels like hydrogen,

methane, methanol, etc. directly into electrical energy are called fuel cells.

b)i) The amount of chemical reaction which occurs at any electrode during electrolysis by a

current is proportional to the quantity of electricity passed through the electrolyte (solution or

melt).

ii) Limiting molar conductivity of an electrolyte can be represented as the sum of the individual

contributions of the anion and cation of the electrolyte.

OR

1

1

1

1

1

Page 112: Chemistry Past Papers

5

24 a) Degree of dissociation is the extent to which electrolyte gets dissociated into its constituent

ions.

b) E

0cell = E

0Ag+ / Ag - E

0Ni2+ / Ni

= 0.80V – 0.25V

= 0.55V

1og Kc =

=

log Kc = 18.644

∆G0 = - nFE

0cell

= -2x96500 Cmol-1

x 0.55V

= -106,150 Jmol-1

Max.work =+106150 Jmol-1

or 106.150k Jmol-1

1

1

½

½

½

½

1

25 a) i)

ii)

b) i) Due to absence of d-orbital, nitrogen cannot expand its valency beyond four.

ii) Because of pπ – pπ multiple bonding in dioxygen which is absent in sulphur.

iii) Due to excitation of electron by absorption of radiation from visible region. OR

1

1

1

1

1

25 a) i)

ii)

b) It is manufactured by Contact Process which involves following steps:

i) burning of sulphur or sulphide ores in air to generate SO2.

ii) conversion of SO2 to SO3 by the reaction with oxygen in the presence of a catalyst (V2O5)

iii) absorption of SO3 in H2SO4 to give Oleum (H2S2O7). The oleum obtained is diluted to give

sulphuric acid

Reaction condition – pressure of 2 bar and temperature of 720 K

Catalyst used is V2O5

Yield – 96 – 98% pure

1

1

1

1

1

26 a) i) Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are

heated with sodalime (NaOH and CaO).

ii) When the alkyl / acyl group is introduced at ortho and para positions by reaction

with alkyl halide / acyl halide in the presence of anhydrous aluminium chloride (a Lewis

acid) as catalyst.

1

Page 113: Chemistry Past Papers

6

(Note : Award full marks if correct equation is given )

b) i)

ii)

iii)

(or any other correct method)

OR

1

1

1

1

26 a) i) When the acyl groups are introduced at ortho and para positions by reaction with acyl halide in the

presence of anhydrous aluminium chloride (a Lewis acid) as catalyst.

ii) Aldehydes and ketones having at least one -hydrogen undergo a reaction in the presence of

dilute alkali as catalyst to form -hydroxy aldehydes (aldol) or hydroxy ketones (ketol),

respectively.

(Note : Award full marks if correct equation is given )

b)i)

1

1

1

Page 114: Chemistry Past Papers

7

ii)

iii) CH3COCl

1

1

Page 115: Chemistry Past Papers

56/2/3/F 1 P.T.O.

narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð >na Adí` bIo§ & Candidates must write the Code on the

title page of the answer-book.

Series SSO/2 H$moS> Z§.

Code No.

amob Z§. Roll No.

agm`Z dkmZ (g¡ÕmpÝVH$)

CHEMISTRY (Theory)

ZYm©[aV g_` : 3 KÊQ>o AYH$V_ A§H$ : 70

Time allowed : 3 hours Maximum Marks : 70

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _o§ _wÐV n¥ð> 15 h¢ &

àíZ-nÌ _| XmhZo hmW H$s Amoa XE JE H$moS >Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na bI| &

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _| >26 àíZ h¢ & H¥$n`m àíZ H$m CÎma bIZm ewê$ H$aZo go nhbo, àíZ H$m H«$_m§H$ Adí` bI| &

Bg àíZ-nÌ H$mo n‹T>Zo Ho$ bE 15 _ZQ >H$m g_` X`m J`m h¡ & àíZ-nÌ H$m dVaU nydm©• _| 10.15 ~Oo H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg AdY Ho$ Xm¡amZ do CÎma-nwpñVH$m na H$moB© CÎma Zht bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

Please check that this question paper contains 26 questions.

Please write down the Serial Number of the question before

attempting it.

15 minute time has been allotted to read this question paper. The question

paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

56/2/3/F

SET-3

Page 116: Chemistry Past Papers

56/2/3/F 2

gm_mÝ` ZXe :

(i) g^r àíZ AZdm`© h¢ &

(ii) àíZ g§»`m 1 go 5 VH$ AV bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 1 A§H$ h¡ &

(iii) àíZ g§»`m 6 go 10 VH$ bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 2 A§H$ h¡§ &

(iv) àíZ g§»`m 11 go 22 VH$ ^r bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 3 A§H$ h¢ &

(v) àíZ g§»`m 23 _yë`mYm[aV àíZ h¡ Am¡a BgHo$ bE 4 A§H$ h¢ &

(vi) àíZ g§»`m 24 go 26 VH$ XrK©-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 5 A§H$ h¢ &

(vii) `X Amdí`H$Vm hmo, Vmo bm°J Q>o~bm| H$m à`moJ H$a| & H¡$ëHw$boQ>am| Ho$ Cn`moJ H$s AZw_V Zht h¡ &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 5 are very short answer questions and carry

1 mark each.

(iii) Questions number 6 to 10 are short answer questions and carry 2 marks

each.

(iv) Questions number 11 to 22 are also short answer questions and carry

3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Questions number 24 to 26 are long answer questions and carry 5 marks

each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. Cg `m¡JH$ H$m gyÌ Š`m h¡ Og_| VÎd Y ccp OmbH$ ~ZmVm h¡ Am¡a X Ho$ na_mUw

AîQ>\$bH$s` [a>º$ H$m 2/3dm± ^mJ KoaVo h¢ ? 1

What is the formula of a compound in which the element Y forms ccp

lattice and atoms of X occupy 2/3rd of octahedral voids ?

Page 117: Chemistry Past Papers

56/2/3/F 3 P.T.O.

2. XE JE `m¡JH$ H$m AmB©.`y.nr.E.gr. Zm_ bIE : 1

HO CH2 CH = C CH3

CH3

Write the IUPAC name of the given compound :

HO CH2 CH = C CH3

CH3

3. ^m¡VH$emofU CËH«$_Ur` h¡ O~H$ amgm`ZH$emofU AZwËH«$_Ur` hmoVm h¡ & Š`m| ? 1

Physisorption is reversible while chemisorption is irreversible. Why ?

4. ZåZbIV `w½_ _| H$m¡Z SN2 A^H«$`m AYH$ Vrd«Vm go H$aoJm Am¡a Š`m| ? 1

CH3 CH2 Br Am¡a CH3 CH2 I

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 CH2 Br and CH3 CH2 I

5. gm_mÝ` Vmn_mZ na gë\$a H$m H$m¡Z-gm Anaê$n (EbmoQ´>mon) D$î_r` ê$n go ñWm`r h¡ ? 1

Which allotrope of sulphur is thermally stable at room temperature ?

6. (a) Obr` H$m°na(II) ŠbmoamBS> db`Z Ho$ dÚwV ²-AnKQ>Z Ho$ Xm¡amZ H¡$WmoS> na ZåZbIV A^H«$`mE± hmoVr h¢ :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

CZHo$ _mZH$ AnM`Z BboŠQ´>moS> d^d (E0) Ho$ _mZm| Ho$ AmYma na H¡$WmoS> na H$g

A^H«$`m H$s g§^mdZm (gwg§JVVm) h¡ Am¡a Š`m| ?

(b) Am`Zm| Ho$ ñdV§Ì A^J_Z Ho$ H$mobamD$e Z`_ H$m H$WZ H$sOE & BgH$m EH$ AZwà`moJ bIE & 2

Page 118: Chemistry Past Papers

56/2/3/F 4

(a) Following reactions occur at cathode during the electrolysis of

aqueous copper(II) chloride solution :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

On the basis of their standard reduction electrode potential (E0)

values, which reaction is feasible at the cathode and why ?

(b) State Kohlrausch law of independent migration of ions. Write its

one application.

7. g§H«$_U VÎd Š`m| n[adVu CnM`Z AdñWmAm§o H$mo àXe©V H$aVo h¢ ? 3d loUr _| (Sc go Zn)

H$m¡Z-gm VÎd gdm©YH$ CnM`Z AdñWmE± Xem©Vm h¡ Am¡a Š`m| ? 2

Why do transition elements show variable oxidation states ? In 3d series

(Sc to Zn), which element shows the maximum number of oxidation

states and why ?

8. (i) ZåZbIV H$m°åßboŠg H$m AmB©.`y.nr.E.gr. Zm_ bIE :

[Cr (en)3]Cl3

(ii) ZåZbIV H$m°åßboŠg H$m gyÌ bIE :

nmoQ>¡e`_ Q´>mB© Am°Šgb¡Q>mo H«$mo_oQ>(III) 2

(i) Write down the IUPAC name of the following complex :

[Cr (en)3]Cl3

(ii) Write the formula for the following complex :

Potassium tri oxalato chromate(III)

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56/2/3/F 5 P.T.O.

9. ZåZbIV A^H«$`mAm| _| à`moJ AmZo dmbo A^H$maH$m| Ho$ Zm_ XrOE : 2

(i) CH3 CHO ?

CH3 CH CH3

|

OH

(ii) CH3 COOH ?

CH3 COCl

Name the reagents used in the following reactions :

(i) CH3 CHO ?

CH3 CH CH3 |

OH

(ii) CH3 COOH ?

CH3 COCl

10. amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ go Š`m VmËn`© h¡ ? EH$ CXmhaU XrOE & G$UmË_H$ dMbZ Ho$ bE ∆mixH H$m Š`m M• hmoVm h¡ ? 2>

AWdm EµOAmoQ´>mon H$mo n[a^mfV H$sOE & amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ Ûmam ~ZZo dmbm EµOAmoQ´>mon H$g àH$ma H$m hmoVm h¡ ? EH$ CXmhaU XrOE & 2

What is meant by negative deviation from Raoult’s law ? Give an

example. What is the sign of mixH for negative deviation ?

OR

Define azeotropes. What type of azeotrope is formed by negative

deviation from Raoult’s law ? Give an example.

11. (a) EpëH$b h¡bmBS>| Ob _| KwbZerb Zht h¢ & Š`m| ?

(b) ã`wQ>¡Z-1-Am°b àH$meH$s` ZpîH«$` (Y«wdU AKyU©H$) h¡ naÝVw ã`wQ>¡Z-2-Am°b

àH$meH$s` gH«$` (Y«wdU KyU©H$) h¡ & Š`m| ?

(c) `Ún ŠbmoarZ BboŠQ´>m°Z H$mo AmH$f©V H$aZo dmbm J«wn h¡ \$a ^r `h BboŠQ´>m°ZñZohr

Eamo_¡Q>H$ àVñWmnZ A^H«$`mAm| _| Am°Wm- VWm n¡am- ZXeH$ h¡ & Š`m| ? 3

(a) Why are alkyl halides insoluble in water ?

(b) Why is Butan-1-ol optically inactive but Butan-2-ol is optically

active ?

(c) Although chlorine is an electron withdrawing group, yet it is

ortho-, para- directing in electrophilic aromatic substitution

reactions. Why ?

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56/2/3/F 6

12. ZåZbIV H$m ê$nm§VaU Amn H¡$go H$a|Jo : 3

(i) ~oݵOmoBH$ EgS> H$mo ~oݵO¡pëS>hmBS> _|

(ii) EWmB©Z H$mo EW¡Z¡b _|

(iii) EogrQ>H$ EgS> H$mo _rWoZ _|

AWdm

ZåZbIV A^H«$`mAm| go gå~pÝYV g_rH$aUm| H$mo bIE : 3

(i) ñQ>r\$Z A^H«$`m

(ii) dmoë\$-H$íZa AnM`Z

(iii) EQ>mS>© A^H«$`m

How do you convert the following :

(i) Benzoic acid to Benzaldehyde

(ii) Ethyne to Ethanal

(iii) Acetic acid to Methane

OR

Write the equations involved in the following reactions :

(i) Stephen reaction

(ii) Wolff-Kishner reduction

(iii) Etard reaction

13. 37·2 g Ob _| NaCl (_mob Ðì`_mZ = 58·5 g mol1) H$s H$VZr _mÌm KwbmB© OmE H$ h_m§H$ 2°C KQ> OmE, `h _mZVo hþE H$ NaCl nyU© ê$n go dKQ>V hmoVm h¡ ?

(Kf Ob Ho$ bE = 1·86 K kg mol1) 3

Calculate the mass of NaCl (molar mass = 58·5 g mol1) to be dissolved in

37·2 g of water to lower the freezing point by 2C, assuming that NaCl

undergoes complete dissociation. (Kf for water = 1·86 K kg mol1)

Page 121: Chemistry Past Papers

56/2/3/F 7 P.T.O.

14. ZåZbIV ~hþbH$m| Ho$ EH$bH$m| Ho$ Zm_ Am¡a CZH$s g§aMZmE± bIE : 3

(i) Q>oarbrZ (ii) ~¡Ho$bmBQ> (iii) ~wZm-S

Write the names and structures of the monomers of the following

polymers :

(i) Terylene

(ii) Bakelite

(iii) Buna-S

15. (i) ZåZbIV _§o H$m¡Z _moZmog¡Ho$amBS> h¡ : ñQ>mM©, _mëQ>mog, \«$ŠQ>mog, gobwbmog

(ii) Aåbr` Eo_Zmo EogS>m| Am¡a jmar` Eo_Zmo EogS>m| Ho$ ~rM$ Š`m A§Va hmoVm h¡ ?

(iii) Cg dQ>m_Z H$m Zm_ bIE OgH$s H$_r Ho$ H$maU _gy‹S>m| _| IyZ AmZo bJVm h¡ & 3

(i) Which one of the following is a monosaccharide :

starch, maltose, fructose, cellulose

(ii) What is the difference between acidic amino acids and basic amino

acids ?

(iii) Write the name of the vitamin whose deficiency causes bleeding of

gums.

16. (i) H$m°åßboŠg [Pt(en)2Cl2]2+ Ho$ Á`m_Vr` g_md`dm| H$mo AmaoIV H$sOE &

(ii) H«$ñQ>b \$sëS> gÕmÝV Ho$ AmYma na `X ∆o > P h¡, Vmo d4 Am`Z H$m BboŠQ´>m°ZH$ dÝ`mg bIE &

(iii) H$m°åßboŠg [Ni(CN)4]2 H$m g§H$aU àH$ma Am¡a Mwå~H$s` ì`dhma bIE & (Ni H$m na_mUw H«$_m§H$ = 28) 3

(i) Draw the geometrical isomers of complex [Pt(en)2Cl2]2+.

(ii) On the basis of crystal field theory, write the electronic

configuration for d4 ion, if o P.

(iii) Write the hybridization type and magnetic behaviour of the

complex [Ni(CN)4]2. (Atomic number of Ni = 28)

Page 122: Chemistry Past Papers

56/2/3/F 8

17. (i) ZH$b Ho$ n[aîH$aU _| H$m_ AmZo dmbr dY Ho$ nrN>o Omo gÕmÝV hmoVm h¡ CgH$m

C„oI H$sOE &

(ii) gmoZo Ho$ ZîH$f©U _| VZw NaCN H$s Š`m ^y_H$m hmoVr h¡ ?

(iii) ‘H$m°na _¡Q>o’ Š`m hmoVm h¡ ? 3

(i) Indicate the principle behind the method used for the refining of

Nickel.

(ii) What is the role of dilute NaCN in the extraction of gold ?

(iii) What is ‘copper matte’ ?

18. 25C na ZåZ gob H$m dÚwV²-dmhH$ ~b (B©.E_.E\$.) n[aH$bV H$sOE : 3

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

Calculate the emf of the following cell at 25C :

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

19. ZåZbIV A^H«$`mAm| Ho$ CËnmXm| H$s àmJwº$ H$sOE : 3

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

Predict the products of the following reactions :

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

Page 123: Chemistry Past Papers

56/2/3/F 9 P.T.O.

20. EH$ VÎd X (_moba Ðì`_mZ = 60 g mol1) H$m KZËd 6·23 g cm3 h¡ & `X `yZQ> gob Ho$ H$moa H$s bå~mB© 4 × 108 cm h¡, Vmo Š`y~H$ `yZQ> gob Ho$ àH$ma H$s Š`m nhMmZ hmoJr ? 3

An element X (molar mass = 60 g mol1) has a density of 6.23 g cm3.

Identify the type of cubic unit cell, if the edge length of the unit cell is

4 × 108 cm.

21. (a) ZåZbIV H$mo Amn H$maU XoVo hþE H¡$go g_PmE±Jo :

(i) Mn H$m CƒV_ âbwAmoamBS> MnF4 h¡ O~H$ CƒV_ Am°ŠgmBS> Mn2O7

h¡ &

(ii) g§H«$_U YmVwE± Am¡a CZHo$ `m¡JH$ CËàoaH$ JwUY_© Xem©Vo h¢ &

(b) ZåZbIV g_rH$aU H$mo nyU© H$sOE :

3–2

4MnO + 4H+ 3

(a) How would you account for the following :

(i) Highest fluoride of Mn is MnF4 whereas the highest oxide is

Mn2O7.

(ii) Transition metals and their compounds show catalytic

properties.

(b) Complete the following equation :

3–2

4MnO + 4H+

22. ZåZbIV AdbmoH$Zm| Ho$ bE H$maUm| H$mo XrOE : 3

(i) g_wÐr Ob Am¡a ZXr H$m Ob Ohm± _bVo h¢ dhm± EH$ S>oëQ>m ~Z OmVm h¡ &

(ii) MmaH$mob H$s gVh na N2 J¡g H$s Anojm NH3 J¡g AYH$ erK«Vm go AYemofV hmoVr h¡ &

(iii) MyU© H$E hþE nXmW© AYH$ à^mdembr AYemofH$ hmoVo h¢ &

Page 124: Chemistry Past Papers

56/2/3/F 10

Give reasons for the following observations :

(i) A delta is formed at the meeting point of sea water and river

water.

(ii) NH3 gas adsorbs more readily than N2 gas on the surface of

charcoal.

(iii) Powdered substances are more effective adsorbents.

23. ~ƒm| _| _Yw_oh Am¡a CXmgr Ho$ ~‹T>Vo Ho$gm| H$mo XoIZo Ho$ ~mX EH$ àgÕ ñHy$b Ho$ qàgnb

lr Mmon ‹S>m Zo EH$ go_Zma H$m Am`moOZ H$`m Og_| CÝhm|Zo ~ƒm| Ho$ A^^mdH$m| VWm AÝ`

ñHy$bm| Ho$ qàgnbm| H$mo Am_§ÌV H$`m & CÝhm|Zo ñHy$bm| _| g ‹S>o hþE ^moÁ` nXmWm] (O§H$ \y$S>) na àV~§Y bJmZo H$m ZU©` b`m, gmW hr `h ZU©` b`m H$ ñHy$bm| _| ñdmñÏ`dY©H$

nXmW© O¡go gyn, bñgr, XÿY AmX H¢$Q>rZm| _| CnbãY H$amB© OmE± & CÝhm|Zo `h ^r ZU©`

b`m H$ àmV:H$mbrZ Egoå~br Ho$ g_` ~ƒm| H$mo àVXZ AmYo K§Q>o H$s emar[aH$ H$gaV ^r H$amB© OmE & N>: _mh níMmV² lr Mmon ‹S>m Zo ~ƒm| Ho$ ñdmñÏ` H$m AYH$V_ dÚmb`m| _|

nwZ: ZarjU H$adm`m Am¡a ~ƒm| Ho$ ñdmñÏ` _| AZwn_ gwYma nm`m J`m &

Cn w©º$ àH$aU H$mo n‹T>Zo Ho$ ~mX, ZåZbIV àíZm| Ho$ CÎma XrOE : 4

(i) lr Mmon ‹S>m Ûmam H$Z _yë`m| (H$_-go-H$_ Xmo) H$mo Xem©`m J`m h¡ ?

(ii) EH$ dÚmWu Ho$ ê$n _|, Amn Bg df` _| H¡$go OmJê$H$Vm \¡$bmE±Jo ?

(iii) AdZ_Z-damoYr S´>J ~Zm S>m°ŠQ>a H$s gbmh Ho$ Š`m| Zht boZ o MmhE ?

(iv) H¥$Ì_ _YwaH$ Ho$ Xmo CXmhaU XrOE &

Seeing the growing cases of diabetes and depression among children,

Mr. Chopra, the principal of one reputed school organized a seminar in

which he invited parents and principals. They all resolved this issue by

strictly banning the junk food in schools and by introducing healthy

snacks and drinks like soup, lassi, milk etc. in school canteens. They also

decided to make compulsory half an hour physical activities for the

students in the morning assembly daily. After six months,

Mr. Chopra conducted the health survey in most of the schools and

discovered a tremendous improvement in the health of students.

Page 125: Chemistry Past Papers

56/2/3/F 11 P.T.O.

After reading the above passage, answer the following questions :

(i) What are the values (at least two) displayed by Mr. Chopra ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) Why should antidepressant drugs not be taken without consulting

a doctor ?

(iv) Give two examples of artificial sweeteners.

24. (a) àË`oH$ Ho$ bE Cn wº$ CXmhaU XoVo hþE ZåZbIV A^H«$`mAm| H$mo àXe©V H$sOE :

(i) A_moZrH$aU

(ii) H$pßb¨J (`w½_Z) A^H«$`m

(iii) Eo_rZm| H$m EogrQ>brH$aU

(b) àmW_H$ (àmB_ar), ÛVr`H$ (goH$ÊS>ar) Am¡a V¥Vr`H$ (Q>e©`ar) E_rZm| H$s nhMmZ H$aZo Ho$ bE hÝg~J© dY H$m dU©Z H$sOE & gå~Õ A^H«$`mAm| Ho$ amgm`ZH$ g_rH$aUm| H$mo ^r bIE & 5

AWdm

(a) O~ ~oݵOrZ S>mBEµOmoZ`_ ŠbmoamBS> (C6 H5–

2ClN ) ZåZbIV A^H$maH$m| go

A^H«$`m H$aVm h¡, V~ àmßV _w»` CËnmXm| H$s g§aMZmE± bIE :

(i) HBF4 /

(ii) Cu / HBr

(b) ZåZbIV A^H«$`mAm| _| A, B Am¡a C H$s g§aMZmE± bIE :

5

Page 126: Chemistry Past Papers

56/2/3/F 12

(a) Illustrate the following reactions giving suitable example in each

case :

(i) Ammonolysis

(ii) Coupling reaction

(iii) Acetylation of amines

(b) Describe Hinsberg method for the identification of primary,

secondary and tertiary amines. Also write the chemical equations

of the reactions involved.

OR

(a) Write the structures of main products when benzene diazonium

chloride (C6 H5–

2ClN ) reacts with the following reagents :

(i) HBF4 /

(ii) Cu / HBr

(b) Write the structures of A, B and C in the following reactions :

25. (a) ZåZbIV nXm| H$mo n[a^mfV H$sOE :

(i) gH«$`U D$Om©

(ii) Xa pñWam§H$

(b) 25% d`moOZ Ho$ bE EH$ àW_ H$moQ> H$s A^H«$`m 10 _ZQ> boVr h¡ & A^H«$`m Ho$ bE t

1/2 H$m n[aH$bZ H$sOE >& 5

(X`m J`m : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

AWdm

Page 127: Chemistry Past Papers

56/2/3/F 13 P.T.O.

(a) EH$ amgm`ZH$ A^H«$`m R P Ho$ bE gm§ÐU _| n[adV©Z ln [R] vs. g_` (s) ZrMo ßbm°Q> _| X`m J`m h¡ :

ln [R]

t (s)

(i) A^H«$`m H$s H$moQ> H$s àmJwº$ H$sOE &

(ii) dH«$ H$m T>bmZ Š`m h¡ ?

(iii) A^H«$`m Ho$ bE Xa pñWam§H$ H$s `yZQ> bIE &

(b) Xem©BE H$ 99% nyU© hmoZo _| Omo g_` bJVm h¡ dh Cg g_` H$m XwJwZm h¡ Omo

A^H«$`m Ho$ 90% nyU© hmoZo _| bJVm h¡ & 5

(a) Define the following terms :

(i) Activation energy

(ii) Rate constant

(b) A first order reaction takes 10 minutes for 25% decomposition.

Calculate t1/2

for the reaction.

(Given : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

OR

(a) For a chemical reaction R P, the variation in the concentration,

ln [R] vs. time (s) plot is given as

ln [R]

t (s)

Page 128: Chemistry Past Papers

56/2/3/F 14

(i) Predict the order of the reaction.

(ii) What is the slope of the curve ?

(iii) Write the unit of rate constant for this reaction.

(b) Show that the time required for 99% completion is double of the

time required for the completion of 90% reaction.

26. (a) ZåZbIV Ho$ H$maU XoVo hþE ñnîQ> H$sOE :

(i)

4NH _| Omo Am~ÝY H$moU h¡ dh NH3 Ho$ H$moU go CƒVa h¡ &

(ii) H2O H$s Anojm H2S H$m ŠdWZm§H$ Ý`yZVa h¡ &

(iii) AnM`Z ì`dhma SO2 go TeO2 H$s Amoa KQ>Vm h¡ &

(b) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) H4P2O7 (nm`amo\$m°ñ\$mo[aH$ EogS>)

(ii) XeF2 5

AWdm

(a) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) XeF4

(ii) H2S2O7

(b) ZåZbIV Ho$ H$maU XrOE :

(i) HCl go A^H«$`m go Am`aZ FeCl2 ~ZmVm h¡ Z H$s FeCl3.

(ii) HClO H$s Anojm HClO4 à~bVa Aåb h¡ &

(iii) dJ© 15 Ho$ g^r hmBS´>mBS>m| _| BiH3 à~bV_ AnMm`H$ h¡ & 5

(a) Account for the following :

(i) Bond angle in

4NH is higher than NH3.

(ii) H2S has lower boiling point than H2O.

(iii) Reducing character decreases from SO2 to TeO2.

Page 129: Chemistry Past Papers

56/2/3/F 15 P.T.O.

(b) Draw the structures of the following :

(i) H4P2O7 (Pyrophosphoric acid)

(ii) XeF2

OR

(a) Draw the structures of the following :

(i) XeF4

(ii) H2S2O7

(b) Account for the following :

(i) Iron on reaction with HCl forms FeCl2 and not FeCl3.

(ii) HClO4 is a stronger acid than HClO.

(iii) BiH3 is the strongest reducing agent amongst all the

hydrides of group 15.

Page 130: Chemistry Past Papers

1

Qn Value points Marks

1 X2Y3 1

2 3-Methylbut-2-en-1-ol 1

3 Because of weak van der Waals’ forces in physisorption whereas there are strong chemical

forces in chemisorption.

1

4 CH3CH2I , because I is a better leaving group. ½ , ½

5 Rhombic sulphur 1

6 a) Cu2+

(aq) + 2 e Cu(s) because of high E0 value/ more negative ∆G

b) It states that limiting molar conductivity of an electrolyte is equal to the sum of the individual

contributions of cations and anions of the electrolyte.

It is used to calculate the Ʌm0 for weak electrolyte / It is used to calculate α and Kc

(Any one application)

½ , ½

1

1

7 a) Due to presence of unpaired d-electrons/ comparable energies of 3d and 4s orbitals.

b) Mn , due to involvement of 4s and 3d electrons/ presence of maximum unpaired d-

electrons.

1

½ ,½

8 i) tris-(ethane-1,2-diamine)chromium(III) chloride

ii) K3[ Cr(C2O4)3]

1

1

9 (i) CH3MgBr/ H3O+

(ii) PCl5/ PCl3 / SOCl2

1

1

10

10

When solute- solvent interaction is stronger than pure solvent or solute interaction.

Eg: chloroform and acetone (or any other correct eg)

∆mixH= negative

OR

Azeotropes –binary mixtures having same composition in liquid and vapour phase and boil at

constant temperature / is a liquid mixture which distills at constant temperature without

undergoing change in composition

1

½

½

1

½

CHEMISTRY MARKING SCHEME 2015

SET -56/2/3 F

Page 131: Chemistry Past Papers

2

Maximum boiling azeotropes

eg: HNO3 (68%) and H2O(32%) (or any other correct example)

½

11 a) Because they are unable to form H-bonds with water molecules.

b) Because of the presence of chiral carbon in butan-2-ol.

c) Due to dominating +R effect

1

1

1

12 i) C6H5COOH PCl5 C6H5COCl H2/Pd C6H5CHO

BaSO4

ii) CH≡CH + H2O Hg2+

/H2SO4 CH3CHO

iii) CH3COOH NaOH

CH3COONa NaOH + CaO , heat

CH4

OR

i)

ii)

iii)

1

1

1

1

1

1

13 ∆ Tf = i. Kf m

= i Kf wB x 1000

MB x wA

2K= 2 x 1.86K kg/mol x wB x 1000

58.5 g/mol x 37.2 g

wB = 1.17g

1

1

1

14

i)

ii)

Phenol and formaldehyde

1

1

Page 132: Chemistry Past Papers

3

iii)

(Note: half mark for structure/s and half mark for name/s)

1

15 i) Fructose

ii) Acidic amino acid has more number of acidic carboxylic group than basic amino

group whereas basic amino acid has more number of basic amino group.

iii) Vitamin C

1

1

1

16

i)

cis- isomer trans-isomer

ii) t2g4

iii) dsp 2

, diamagnetic

1

1

½ , ½

17 a) Impure Ni reacts with CO to form volatile Ni(CO)4 which when heated at higher

temperature decomposes to give pure Ni.

b) NaCN acts as a leaching agent to form a soluble complex with gold.

c) It is a mixture of Cu2S and FeS

1

1

1

18 E cell = E

0 cell –

log

E cell = 0.76 V -

V log

( )

E cell = 0.76 – 0.0295 V log 10

= 0.7305 V

1

1

1

19 i) CH3CH2CH2OH

ii)

1

1

Page 133: Chemistry Past Papers

4

iii) CH3CHO

1

20 d=

6.23 g cm-3

=

( )

z=4

fcc

½

½

1

1

21 i) Because oxygen stabilizes Mn more than F due to multiple bonding

ii) Because of their ability to show variable oxidation state(or any other correct reason)

iii) 3MnO42-

+ 4H+ 2MnO4

- + MnO2 + 2H2O

1

1

1

22 i) Due to coagulation of colloidal clay particles.

ii) Because NH3 is easily liquefiable than N2 due to its larger molecular size.

iii) Because of more surface area.

1

1

1

23 a) Concern for students health, Application of knowledge of chemistry to daily life, empathy

, caring or any other

b) Through posters, nukkad natak in community, social media, play in assembly (or any other

relevant answer)

c) Wrong choice and overdose may be harmful

d) Aspartame, saccharin (or any other correct example)

½ , ½

1

1

½+ ½

24

a) i)ammonolysis

ii)

1

1

Page 134: Chemistry Past Papers

5

24

(any one)

iii) (or any other correct reaction)

b)reaction of primary amine

(soluble in alkali)

Reaction of secondary amine

(insoluble in alkali)

Tertiary amine doesn’t react

OR

a) i)

ii)

1

1

1

1

1

½,½,

½

Page 135: Chemistry Past Papers

6

b) i) A- B- C-

ii) A- CH3CN B- CH3CH2NH2 C- CH3CH2OH

½ ,½,

½

25 a)i) Activation energy- Extra energy required by reactants to form activated complex.

ii) Rate constant- rate of reaction when the concentration of reactant is unity.

b)

k= 2.303 log [ A0 ]

t [A]

k = 2.303 log 100

10 min 75

k = 2.303 x 0.125

10 min

k = 0.02879 min-1

t1/2 =

=

t1/2 = 24.07min

OR

a) i)First order ii) -k iii) s-1

b)

t =

log

t99% =

log

t =

x 2

1

1

½

½

1

1

1,1,1

½

Page 136: Chemistry Past Papers

7

t90% =

log

=

t99% = 2 x t90%

½

1

26 a) i)Because of lone pair in NH3 , lone pair- bond pair repulsion decreases the bond angle

ii)Because of absence of H-bonding in H2S

iii)Because stability of +4 oxidation state increases from SO2 to TeO2

b)

OR

a)

b)i)Because iron on reaction with HCl produces H2(g) which prevents the formation of FeCl2 to

FeCl3 / Because HCl is a weak oxidising agent.

ii) Because of higher oxidation state of chlorine in HClO4

iii) Because of lower dissociation enthalpy of Bi-H bond.

1

1

1

1,1

1,1

1

1

1

Page 137: Chemistry Past Papers

8

Page 138: Chemistry Past Papers

56/1/1/D 1 [P.T.O.

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(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú»ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1 ÛúÖê›ü ®ÖÓ. Code No.

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• ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë …

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• ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê ×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

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• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will only read the

question paper and will not write any answer on the answer-book during this period.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

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56/1/1/D 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. no. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. no. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. no. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. no. 23 is a value based question and carry 4 marks.

(vi) Q. no. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculators is not allowed.

1. H3PO4 Ûúß õÖÖ¸üÛúŸÖÖ ŒµÖÖ Æîü ? 1

What is the basicity of H3PO4 ?

2. פüµÖê ÝÖµÖê µÖÖî×ÝÖÛú ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö ×»Ö×ÜÖ‹ : 1

Write the IUPAC name of the given compound :

3. ×®Ö´®Ö µÖãÝ´Ö ´Öë ÛúÖî®Ö SN2 †×³Ö×ÛÎúµÖÖ †×¬ÖÛú ŸÖß¾ÖΟÖÖ ÃÖê Ûú êüÝÖÖ †Öî ü ŒµÖÖë ? 1

CH3 – CH2 – Br ŸÖ£ÖÖ CH3 –

C|

C|

B

H3

r

CH3

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 – CH2 – Br and CH3 –

C|

C|

B

H3

r

CH3

Page 140: Chemistry Past Papers

56/1/1/D 3 [P.T.O.

4. BaCl2 †Öî ü KCl ´Öë ÃÖê ÛúÖî®Ö ŠúÞÖÖŸ´ÖÛú “ÖÖ•ÖÔ ¾ÖÖ»Öê ÛúÖê»ÖÖ‡›üß ÃÖÖò»Ö ÛúÖ ÃÛÓú¤ü®Ö †×¬ÖÛú ¯ÖϳÖÖ¾Ö¿ÖÖ»Öß œÓüÝÖ ÃÖê Ûú¸êüÝÖÖ ? ÛúÖ¸üÞÖ ¤üßו֋ … 1

Out of BaCl2 and KCl, which one is more effective in causing coagulation of a

negatively charged colloidal Sol ? Give reason.

5. ˆÃÖ µÖÖî×ÝÖÛú ÛúÖ ÃÖæ¡Ö ŒµÖÖ ÆüÖêÝÖÖ ×•ÖÃÖ´Öë Y ŸÖ¢¾Ö ccp •ÖÖ»ÖÛú ²Ö®ÖÖŸÖÖ Æîü †Öî ü X “ÖŸÖã±ú»ÖÛúßµÖ ×¸ü׌ŸÖ ÛúÖ 1/3¾ÖÖÑ ³ÖÖÝÖ ‘Öê üŸÖÖ Æîü ? 1

What is the formula of a compound in which the element Y forms ccp lattice and

atoms of X occupy 1/3rd

of tetrahedral voids ?

6. ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾Ö ŒµÖÖ Æïü ? ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾ÖÖë Ûúß ¤üÖê ×¾Ö¿ÖêÂÖŸÖÖ†Öë ÛúÖê ×»Ö×ÜÖ‹ … 2

What are the transition elements ? Write two characteristics of the transition elements.

7. (i) ÛúÖò ¯»ÖêŒÃÖ [Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine) ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö ×»Ö×ÜÖµÖê …

(ii) ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖ ÛúÖ ÃÖæ¡Ö ×»Ö×ÜÖ‹ :

¯Öê®™üÖ‹ê ÖÖ‡®Ö®ÖÖ‡™ÒüÖ‡™üÖê-o-ÛúÖê²ÖÖ»™ü (III). 2

(i) Write down the IUPAC name of the following complex :

[Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine)

(ii) Write the formula for the following complex :

Pentaamminenitrito-o-Cobalt (III).

8. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ¯ÖϵÖãŒŸÖ †×³ÖÛúÖ¸üÛúÖë Ûêú ®ÖÖ´Ö ¤üßו֋ : 2

Name the reagents used in the following reactions :

(i) CH3 – CO – CH3 ?

→ CH3 – C|

O

H

H

– CH3

(ii) C6H5 – CH2 – CH3

?→ C6H5 – COO–K+

9. ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö Ûêú ×»ÖµÖê ∆mixH ÛúÖ ×“ÖÅ®Öü ŒµÖÖ Æîü ? 2

What is meant by positive deviations from Raoult’s law ? Give an example. What is

the sign of ∆mixH for positive deviation ?

†£Ö¾ÖÖ/OR

Page 141: Chemistry Past Papers

56/1/1/D 4

9. ‹×•ÖµÖÖê™ÒüÖê ÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ¯ÖÏÖ¯ŸÖ ‹×•ÖµÖÖê™ÒüÖê Ö ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ

ÆüÖêŸÖÖ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … 2

Define azeotropes. What type of azeotrope is formed by positive deviation from

Raoult’s law ? Give an example.

10. (a) ×ÃÖ»¾Ö¸ü Œ»ÖÖê üÖ‡›ü Ûêú •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö Ûêú ×¾ÖªãŸÖ †¯Ö‘Ö™ü®Ö ´Öë Ûîú£ÖÖê›ü ¯Ö¸ü ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

ˆ®ÖÛêú ´ÖÖ®ÖÛú †¯Ö“ÖµÖ®Ö ‡»ÖꌙÒüÖê›ü ×¾Ö³Ö¾Ö (E°) Ûêú ´ÖÖ®ÖÖë Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü Ûîú£ÖÖê›ü ¯Ö¸ü ×ÛúÃÖ †×³Ö×ÛÎúµÖÖ Ûúß

ÃÖÓ³ÖÖ¾Ö®ÖÖ Æîü †Öî ü ŒµÖÖë ?

(b) ÃÖß´ÖÖÓŸÖ ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾ÖªãŸÖË †¯Ö‘Ö™ËüµÖ Ûúß “ÖÖ»ÖÛúŸÖÖ ÃÖÖÓ¦üÞÖ Ûêú ‘Ö™ü®Öê Ûêú ÃÖÖ£Ö

ŒµÖÖë Ûú´Ö ÆüÖê®Öê »ÖÝÖŸÖß Æîü ? 2

(a) Following reactions occur at cathode during the electrolysis of aqueous silver

chloride solution :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

On the basis of their standard reduction electrode potential (E°) values, which

reaction is feasible at the cathode and why ?

(b) Define limiting molar conductivity. Why conductivity of an electrolyte solution

decreases with the decrease in concentration ?

11. ²ÖꮕÖß®Ö Ûêú 49 g ´Öë ²ÖꮕÖÖê‡Ûú †´»Ö ÛúÖ 3.9 g ‘Öã»Ö®Öê ¯Ö¸ü ×Æü´ÖÖÓÛú ´Öë 1.62 K ÛúÖ †¾Ö®Ö´Ö®Ö ÆüÖê •ÖÖŸÖÖ Æîü … ¾Öî®™ü ÆüÖ±ú ÛúÖ¸üÛú ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ †Öî ü ×¾Ö»ÖêµÖ Ûêú þֳÖÖ¾Ö Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ (ÃÖÓÝÖã×ÞÖŸÖ µÖÖ ×¾Ö‘Ö×™üŸÖ) 3

(פüµÖÖ ÝÖµÖÖ : ²ÖꮕÖÖê‡Ûú ‹×ÃÖ›ü ÛúÖ ´ÖÖê»Ö ¦ü¾µÖ´ÖÖ®Ö = 122 g mol–1, ²ÖꮕÖß®Ö Ûêú ×»ÖµÖê Kf = 4.9 K kg mol–1)

3.9 g of benzoic acid dissolved in 49 g of benzene shows a depression in freezing point

of 1.62 K. Calculate the van’t Hoff factor and predict the nature of solute (associated

or dissociated).

(Given : Molar mass of benzoic acid = 122 g mol–1, Kf for benzene = 4.9 K kg mol–1)

Page 142: Chemistry Past Papers

56/1/1/D 5 [P.T.O.

12. (i) Ø•ÖÛú Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûú¸ü®Öê Ûúß ×¾Ö×¬Ö Ûêú ¯Öß”êû •ÖÖê ×ÃÖ¨üÖ®ŸÖ ÆüÖêŸÖÖ Æîü ˆÃÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ …

(ii) ÛúÖò Ö¸ü Ûêú ×®ÖÂÛúÂÖÔÞÖ ´Öë ×ÃÖ×»ÖÛúÖ Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(iii) ¾µÖÖ¯ÖÖ¸üß »ÖÖêÆü ÛúÖ ×¾Ö¿Öã ü ºþ¯Ö »ÖÖêÆü ÛúÖ ÛúÖî®Ö ºþ¯Ö Æîü ? 3

(i) Indicate the principle behind the method used for the refining of zinc.

(ii) What is the role of silica in the extraction of copper ?

(iii) Which form of the iron is the purest form of commercial iron ?

13. ´ÖÖê»Ö¸ü ¦ü¾µÖ´ÖÖ®Ö 27 g mol–1 Ûêú ÃÖÖ£Ö ‹Ûú ŸÖŸ¾Ö ÛúÖê ü »Ö´²ÖÖ‡Ô 4.05 × 10–8 cm ¾ÖÖ»Öß ‹Ûú ŒµÖæײÖÛú µÖæ×®Ö™ü ÃÖê»Ö ²Ö®ÖÖŸÖÖ Æîü … µÖפü ‘Ö®ÖŸ¾Ö 2.7 g cm–3 ÆüÖê, ŸÖÖê ŒµÖæײÖÛú µÖæ×®Ö™ü ÃÖê»Ö ÛúÖ Ã¾Öºþ¯Ö ŒµÖÖ Æîü ? 3

An element with molar mass 27 g mol–1 forms a cubic unit cell with edge length

4.05 × 10–8 cm. If its density is 2.7 g cm–3, what is the nature of the cubic unit cell ?

14. (a) †Ö¯Ö ×®Ö´®Ö ÛúÖê ÛîúÃÖê ÃÖ´Ö—ÖÖ‹ÑÝÖê ?

(i) »Öï£Öî®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö Ûúß †¯ÖêõÖÖ ‹ê׌™ü®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö †×¬ÖÛú Æîü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¸ÓüÝÖß®Ö µÖÖî×ÝÖÛú ²Ö®ÖÖŸÖß Æïü …

(b) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ : 3

2MnO–

4 + 6H+ + 5NO–

2 →

(a) How would you account for the following :

(i) Actinoid contraction is greater than lanthanoid contraction.

(ii) Transition metals form coloured compounds.

(b) Complete the following equation :

2MnO–

4 + 6H+ + 5NO–

2 →

15. (i) ÛúÖò ¯»ÖêŒÃÖ [Pt(NH3)2Cl2] Ûêú •µÖÖ×´ÖŸÖßµÖ ÃÖ´ÖÖ¾ÖµÖ¾Ö ÛúÖê †Ö êü×ÜÖŸÖ Ûúßו֋ …

(ii) ×ÛÎúÙü»Ö ±úß»›ü ×ÃÖ¨üÖ®ŸÖ Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü µÖפü ∆o < P ÆüÖê ŸÖÖê d4 ÛúÖ ‡»ÖꌙÒüÖò®Ö ×¾Ö®µÖÖÃÖ ×»Ö×ÜÖ‹ …

(iii) ÛúÖò ¯»ÖêŒÃÖ [Ni(CO)4] ÛúÖ ÃÖÓÛú¸üÞÖ †Öî ü “Öã ²ÖÛúßµÖ ¯ÖÏÛéú×ŸÖ ×»Ö×ÜÖ‹ … (¯Ö.ÃÖÓ. Ni = 28) 3

(i) Draw the geometrical isomers of complex [Pt(NH3)2Cl2].

(ii) On the basis of crystal field theory, write the electronic configuration for d4 ion

if ∆o < P.

(iii) Write the hybridization and magnetic behaviour of the complex [Ni(CO)4].

(At.no. of Ni = 28)

Page 143: Chemistry Past Papers

56/1/1/D 6

16. ×®Ö´®Ö ÃÖê»Ö Ûúß 25 °C ¯Ö¸ü emf ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V 3

Calculate emf of the following cell at 25 °C :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V

17. ×®Ö´®Ö †¾Ö»ÖÖêÛú®ÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ¤üßו֋ :

(i) “Ö´ÖÔ¿ÖÖê¬Ö®Ö Ûêú ²ÖÖ¤ü “Ö´Ö›ÌüÖ ÃÖÜŸÖ ÆüÖê •ÖÖŸÖÖ Æîü …

(ii) ¦ü¾Ö ×¾Ö¸üÖê¬Öß ÃÖÖò»Ö Ûúß †¯ÖêõÖÖ ¦ü¾ÖîÖêÆüß ÃÖÖò»Ö †×¬ÖÛú ãÖÖµÖß ÆüÖêŸÖÖ Æîü …

(iii) •Ö²Ö Æîü²Ö¸ü ¯ÖÏÛÎú´Ö «üÖ¸üÖ †´ÖÖê×®ÖµÖÖ ²Ö®ÖÖµÖÖ •ÖÖŸÖÖ Æîü ŸÖ²Ö CO ÛúÖê ¤æü¸ü ¸üÜÖ®ÖÖ †Ö¾Ö¿µÖÛú ÆüÖêŸÖÖ Æîü … 3

Give reasons for the following observations :

(i) Leather gets hardened after tanning.

(ii) Lyophilic sol is more stable than lyophobic sol.

(iii) It is necessary to remove CO when ammonia is prepared by Haber’s process.

18. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö ¾Ö ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖµÖë ×»Ö×ÜÖ‹ :

(i) ®ÖÖµÖ»ÖÖò®Ö-6, 6

(ii) PHBV

(iii) ®Ö߆Öê ÖÏß®Ö 3

Write the names and structures of the monomers of the following polymers :

(i) Nylon-6, 6

(ii) PHBV

(iii) Neoprene

19. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ˆŸ¯ÖÖ¤üÖë Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

? 3

Page 144: Chemistry Past Papers

56/1/1/D 7 [P.T.O.

Predict the products of the following reactions :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

?

20. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ †Ö¯Ö ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ±úß®ÖÖò»Ö ÛúÖê ‹ê×®ÖÃÖÖò»Ö ´Öë

(ii) ¯ÖÏÖê Öî®Ö-2-†Öò»Ö ÛúÖê 2-´Öê×£Ö»Ö¯ÖÏÖê Öî®Ö-2-†Öò»Ö ´Öë

(iii) ‹ê×®Ö»Öß®Ö ÛúÖê ±úß®ÖÖò»Ö ´Öë 3

How do you convert the following :

(i) Phenol to anisole

(ii) Propan-2-ol to 2-methylpropan-2-ol

(iii) Aniline to phenol

†£Ö¾ÖÖ/OR

20. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ Ûúß ×ÛÎúµÖÖ-×¾Ö×¬Ö ÛúÖê ×»Ö×ÜÖ‹ :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) ÃÖî×»Ö×ÃÖ×»ÖÛú ‹ê×ÃÖ›ü Ûêú ‹êÃÖß™üß»ÖßÛú¸üÞÖ ÃÖê ÃÖ´²Ö¨ü ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ×»Ö×ÜÖ‹ … 3

(a) Write the mechanism of the following reaction :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) Write the equation involved in the acetylation of Salicylic acid.

21. (i) ×®Ö´®Ö ´Öë ÃÖê ÛúÖî®Ö ›üÖ‡ÔÃÖîÛêú¸üÖ‡›ü Æîü : ÙüÖ“ÖÔ, ´ÖÖ»™üÖêÃÖ, ±ÏúŒ™üÖêÃÖ, Ý»ÖæÛúÖêÃÖ ?

(ii) ¸êü¿Öê¤üÖ¸ü ¯ÖÏÖê™üß®Ö †Öî ü ÝÖÖê»ÖÖÛúÖ¸ü ¯ÖÏÖê™üß®Ö ´Öë ŒµÖÖ †ÓŸÖ¸ü Æîü ?

(iii) ²Ö““ÖÖë ´Öë ×ÛúÃÖ ×¾Ö™üÖ×´Ö®Ö Ûúß Ûú´Öß Ûêú ÛúÖ¸üÞÖ Æüøüß ´Öë Ûãúºþ¯ÖŸÖÖ ÆüÖê •ÖÖŸÖß Æîü ? 3

(i) Which one of the following is a disaccharide : Starch, Maltose, Fructose,

Glucose ?

(ii) What is the difference between fibrous protein and globular protein ?

(iii) Write the name of vitamin whose deficiency causes bone deformities in children.

Page 145: Chemistry Past Papers

56/1/1/D 8

22. ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤üßו֋ :

(a) t-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›üü Ûúß †¯ÖêõÖÖ n-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›ü ÛúÖ Œ¾Ö£Ö®ÖÖÓÛú ˆ““ÖŸÖ¸ü ÆüÖêŸÖÖ Æîü …

(b) ¸îüÃÖê×´ÖÛú ×´ÖÁÖÞÖ ¯ÖÏÛúÖ¿ÖÛúßµÖ ×®Ö×ÂÛÎúµÖ Æïü …

(c) ®ÖÖ׳ÖÛúîÖêÆüß ¯ÖÏןÖãÖÖ¯Ö®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ¯ÖÏ×ŸÖ Æîü»ÖÖꋸüß®ÖËÃÖ Ûúß ÃÖ×ÛÎúµÖŸÖÖ ²ÖœÌü •ÖÖŸÖß Æîü µÖפü o/p ¯ÖÖê•Öß¿Ö®Ö ¯Ö¸ü ®ÖÖ‡™ÒüÖê ÝÖÏã Ö (–NO2) ˆ¯Ö×Ã£ÖŸÖ ÆüÖê … 3

Give reasons :

(a) n-Butyl bromide has higher boiling point than t-butyl bromide.

(b) Racemic mixture is optically inactive.

(c) The presence of nitro group (–NO2) at o/p positions increases the reactivity of

haloarenes towards nucleophilic substitution reactions.

23. ‹Ûú ¯ÖÏ×ÃÖ¨ü ÃÛæú»Ö Ûêú ׯÖÏØÃÖ¯Ö»Ö ÁÖß ¸üÖµÖ ®Öê ‹Ûú ÃÖê×´Ö®ÖÖ¸ü ÛúÖ †ÖµÖÖê•Ö®Ö ×ÛúµÖÖ †Öî ü ˆÃÖ´Öë ˆ®ÆüÖë®Öê ²Ö““ÖÖë Ûêú

†×³Ö³ÖÖ¾ÖÛúÖë ŸÖ£ÖÖ †Öî ü ÃÛæú»ÖÖë Ûêú ׯÖÏØÃÖ¯Ö»ÖÖë ÛúÖê †Ö´ÖÓ×¡ÖŸÖ ×ÛúµÖÖ †Öî ü ÃÖ²Ö®Öê ×´Ö»ÖÛú¸ü ²Ö““ÖÖë ´Öë ´Ö¬Öã ÖêÆü ŸÖ£ÖÖ

ˆ¤üÖÃÖß •ÖîÃÖß ²Öß´ÖÖ׸üµÖÖë Ûêú ²ÖœÌü®Öê Ûêú ÝÖÓ³Ö߸ü ×¾ÖÂÖµÖ ¯Ö¸ü ×¾Ö“ÖÖ¸-ü×¾Ö´Ö¿ÖÔ ×ÛúµÖÖ … ˆ®ÆüÖë®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ×Ûú ÃÛæú»ÖÖë ´Öë

ÃÖ›Ìêü Æãü‹ ÜÖÖª ¯Ö¤üÖ£ÖÔ ¯Ö¸ü ¯ÖÏןֲ֮¬Ö »ÖÝÖÖµÖÖ •ÖÖµÖê †Öî ü þÖÖãµÖ¾Ö¬ÖÔÛú ¯Ö¤üÖ£ÖÔ •ÖîÃÖê ÃÖæ Ö, »ÖÃÃÖß, ¤æü¬Ö †Öפü ˆ¯Ö»Ö²¬Ö

Ûú¸üÖµÖÖ •ÖÖµÖ … ÃÖÖ£Ö Æüß ÃÛæú»ÖÖë ´Öë ¯ÖÏÖŸÖ:ÛúÖ»Öß®Ö ‹ÃÖê ²Ö»Öß Ûêú ÃÖ´ÖµÖ ²Ö““ÖÖë ÛúÖê †Ö¬Öê ‘ÖÓ™êü Ûúß ¿ÖÖ¸üß׸üÛú ÛúÃÖ¸üŸÖ

Ûú¸üÖ‡Ô •ÖÖµÖê … ”û: ´ÖÖÆü Ûêú ¯Ö¿“ÖÖŸÖË ÁÖß ¸üÖµÖ ®Öê ‹Ûú þÖÖãµÖ ×®Ö¸üßõÖÞÖ ¯Öã®Ö: Ûú¸üÖµÖÖ †Öî ü ¤êüÜÖÖ ÝÖµÖÖ ×Ûú ²Ö““ÖÖë Ûêú

þÖÖãµÖ ´Öë †®Öã Ö´Ö ÃÖã¬ÖÖ¸ü Æãü†Ö Æîü …

ˆ¯Ö¸üÖêŒŸÖ ÛúÖê ¯ÖœÌü®Öê Ûêú ²ÖÖ¤ü ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ÁÖß ¸üÖµÖ «üÖ¸üÖ ×Ûú®Ö ´Ö滵ÖÖë (Ûú´Ö ÃÖê Ûú´Ö ¤üÖê) ÛúÖê ¤ü¿ÖÖÔµÖÖ ÝÖµÖÖ Æîü ?

(ii) ‹Ûú ×¾ÖªÖ£Öá Ûêú ºþ¯Ö ´Öë ‡ÃÖ ×¾ÖÂÖµÖ ´Öë †Ö¯Ö ÛîúÃÖê •ÖÖÝÖºþÛúŸÖÖ ±îú»ÖÖµÖëÝÖê ?

(iii) ¿ÖÖ×®ŸÖÛúÖ¸üÛú ŒµÖÖ Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

(iv) ‹Ã¯Öî™ìü´Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ ŒµÖÖë šÓü›êü ³ÖÖê•µÖ ¯Ö¤üÖ£ÖÔ †Öî ü ¯ÖêµÖ ´Öë Æüß ÃÖß×´ÖŸÖ ÆüÖêŸÖÖ Æîü ? 4

Mr. Roy, the principal of one reputed school organized a seminar in which he invited

parents and principals to discuss the serious issue of diabetes and depression in

students. They all resolved this issue by strictly banning the junk food in schools and

to introduce healthy snacks and drinks like soup, lassi, milk etc. in school canteens.

They also decided to make compulsory half an hour physical activities for the students

in the morning assembly daily. After six months, Mr. Roy conducted the health survey

in most of the schools and discovered a tremendous improvement in the health of

students.

After reading the above passage, answer the following :

(i) What are the values (at least two) displayed by Mr. Roy ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) What are tranquilizers ? Give an example.

(iv) Why is use of aspartame limited to cold foods and drinks ?

Page 146: Chemistry Past Papers

56/1/1/D 9 [P.T.O.

24. (a) ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤êüŸÖê Æãü‹ ïÖ™ü Ûúßו֋ :

(i) HF ÃÖê HI Ûúß †Öê ü †´»ÖßµÖ Ã¾Ö³ÖÖ¾Ö ²ÖœÌüŸÖÖ Æîü …

(ii) †ÖòŒÃÖß•Ö®Ö †Öî ü ÃÖ»±ú¸ü Ûêú ×Æü´ÖÖÓÛú †Öî ü Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²Öß“Ö ²Ö›ÌüÖ †ÓŸÖ¸ü Æîü …

(iii) ®ÖÖ‡™ÒüÖê•Ö®Ö ¯Öê®™üÖÆîü»ÖÖ‡›ëü ®ÖÆüà ²Ö®ÖÖŸÖÖ Æîü …

(b) ×®Ö´®Ö Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) Cl F3

(ii) XeF4 5

(a) Account for the following :

(i) Acidic character increases from HF to HI.

(ii) There is large difference between the melting and boiling points of oxygen

and sulphur.

(iii) Nitrogen does not form pentahalide.

(b) Draw the structures of the following :

(i) Cl F3

(ii) XeF4

†£Ö¾ÖÖ/OR

24. (i) ±úÖòñúÖê üÃÖ ÛúÖ ÛúÖî®Ö ‹»ÖÖê™ÒüÖò Ö †×¬ÖÛú ÃÖ×ÛÎúµÖ Æîü †Öî ü ŒµÖÖë ?

(ii) ÃÖã Ö¸üÃÖÖê×®ÖÛú •Öê™ü ¯»Öê®Ö †Öê•ÖÖê®Ö ¯ÖŸÖÔ Ûêú †¾ÖõÖµÖ Ûêú ×»Ö‹ ÛîúÃÖê וִ´Öê¤üÖ¸ü Æïü ?

(iii) Cl2 Ûúß †¯ÖêõÖÖ F2 Ûúß †Ö²Ö®¬Ö ×¾ÖµÖÖê•Ö®Ö ‹®£ÖÖß Ûú´Ö ŒµÖÖë Æîü ?

(iv) ´ÖÖîÃÖ´Ö×¾Ö–ÖÖ®Ö ´Öë †¾Ö»ÖÖêÛú®Ö Ûêú ×»ÖµÖê ²Öî»Öæ®ÖÖë ´Öë ³Ö¸ü®Öê Ûêú ×»ÖµÖê ×ÛúÃÖ ˆŸÛéú™ü ÝÖîÃÖ ÛúÖ ¯ÖϵÖÖêÝÖ ×ÛúµÖÖ •ÖÖŸÖÖ

Æîü ?

(v) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯Öæ üÖ Ûúßו֋ :

XeF2 + PF5 → 5

(i) Which allotrope of phosphorus is more reactive and why ?

(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone

layers ?

(iii) F2 has lower bond dissociation enthalpy than Cl2. Why ?

(iv) Which noble gas is used in filling balloons for meteorological observations ?

(v) Complete the equation :

XeF2 + PF5 →

Page 147: Chemistry Past Papers

56/1/1/D 10

25. †ÞÖã ÃÖæ¡Ö C7H7ON ÛúÖ ‹Ûú ‹¸üÖê Öê×™üÛú µÖÖî×ÝÖÛú ‘A’ ®Öß“Öê פüµÖê ÝÖµÖê Ûêú †®ÖãÃÖÖ¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÀÖéÓÜÖ»ÖÖ ¤êüŸÖÖ

Æîü … ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë A, B, C, D †Öî ü E Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ : 5

An aromatic compound ‘A’ of molecular formula C7H7ON undergoes a series of

reactions as shown below. Write the structures of A, B, C, D and E in the following

reactions :

†£Ö¾ÖÖ/OR

25. (a) •Ö²Ö ‹×®Ö»Öß®Ö ×®Ö´®Ö †×³ÖÛúÖ¸üÛúÖë Ûêú ÃÖÖ£Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ŸÖ²Ö ´ÖãÜµÖ ˆŸ¯ÖÖ¤üÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) Br2 •Ö»Ö

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) ×®Ö´®Ö ÛúÖê ˆ®ÖÛêú Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ×»Ö×ÜÖ‹ :

C2H5NH2, C2H5OH, (CH3)3N

(c) ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú µÖãÝ´Ö ´Öë ¯ÖÆü“ÖÖ®Ö Ûú¸ü®Öê Ûêú ×»ÖµÖê ‹Ûú ÃÖÖ´ÖÖ®µÖ ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“Ö ¤üßו֋ :

(CH3)2NH †Öî ü (CH3)3N 5

Page 148: Chemistry Past Papers

56/1/1/D 11 [P.T.O.

(a) Write the structures of main products when aniline reacts with the following

reagents :

(i) Br2 water

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) Arrange the following in the increasing order of their boiling point :

C2H5NH2, C2H5OH, (CH3)3N

(c) Give a simple chemical test to distinguish between the following pair of

compounds :

(CH3)2NH and (CH3)3N

26. •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë ´Öê×£Ö»Ö ‹êÃÖß™êü™ü Ûêú •Ö»Ö-†¯Ö‘Ö™ü®Ö Ûêú ×»ÖµÖê ×®Ö´®Ö ¯Ö׸üÞÖÖ´Ö ¯ÖÏÖ¯ŸÖ ÆãüµÖê £Öê :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) פüÜÖ»ÖÖ‡‹ ×Ûú µÖÆü ‹Ûú ”û¤Ëü´Ö ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú †®ÖãÃÖÖ¸ü Æîü ŒµÖÖë×Ûú •Ö»Ö ÛúÖ ÃÖÖÓ¦üÞÖ ×ãָü ¸üÆüŸÖÖ

Æîü …

(ii) ÃÖ´ÖµÖ 30 ÃÖê 60 ÃÖêÛúÞ›ü Ûêú ²Öß“Ö †×³Ö×ÛÎúµÖÖ Ûúß †ÖîÃÖŸÖ ¤ü¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(פüµÖÖ ÝÖµÖÖ Æîü log 2 = 0.3010, log 4 = 0.6021) 5

For the hydrolysis of methyl acetate in aqueous solution, the following results were

obtained :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) Show that it follows pseudo first order reaction, as the concentration of water

remains constant.

(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.

(Given log 2 = 0.3010, log 4 = 0.6021)

†£Ö¾ÖÖ/OR

Page 149: Chemistry Past Papers

56/1/1/D 12

26. (a) ‹Ûú †×³Ö×ÛÎúµÖÖ A + B → P Ûêú ×»ÖµÖê ¤ü¸ü ¤üß ÝÖ‡Ô Æîü

¤ü¸ü = k[A] [B]2

(i) µÖפü B ÛúÖ ÃÖÖÓ¦üÞÖ ¤üÖê ÝÖã®ÖÖ Ûú¸ü פüµÖÖ •ÖÖµÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß ¤ü¸ü ÛîúÃÖê ¯ÖϳÖÖ×¾ÖŸÖ ÆüÖêÝÖß ?

(ii) µÖפü A ²ÖÆãüŸÖ †×¬ÖÛú ´ÖÖ¡ÖÖ ´Öë ´ÖÖî•Öæ¤ü ÆüÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß Ûãú»Ö ÛúÖê×™ü ŒµÖÖ Æîü ?

(b) ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ 50% ¯Öæ üß ÆüÖê®Öê ´Öë 30 ×´Ö®Ö™ü »ÖêŸÖß Æîü … ‡ÃÖ †×³Ö×ÛÎúµÖÖ ÛúÖê 90% ¯ÖæÞÖÔ ÆüÖê®Öê ´Öë

•ÖÖê ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ˆÃÖÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ …

(log 2 = 0.3010) 5

(a) For a reaction A + B → P, the rate is given by

Rate = k[A] [B]2

(i) How is the rate of reaction affected if the concentration of B is doubled ?

(ii) What is the overall order of reaction if A is present in large excess ?

(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time

required for 90% completion of this reaction.

(log 2 = 0.3010)

_________

Page 150: Chemistry Past Papers

Qu

es. Answers Marks

1 BaCl2 because it has greater charge / +2 charge ½ +½

2 X2Y3 1

3 3 1

4 2, 5 - dinitrophenol 1

5 CH3-CH2-Br

Because it is a primary halide / (10) halide

½ +½

6. When vapour pressure of solution is higher than that predicted by Raoult’s law /

the intermolecular attractive forces between the solute-solvent/(A-B) molecules are weaker than

those between the solute-solute and solvent-solvent molecules/A-A or B-B molecules.

Eg. ethanol-acetone/ethanol-cyclohexane/CS2-acetone or any other correct example

ΔmixH is positive

OR

(a)Azeotropes are binary mixtures having the same composition in the liquid and vapour phase

and boil at a constant temperature.

(b) Minimum boiling azeotrope

eg - ethanol + water or any other example

1

½

½

1

½

½

7.

(i)Ag+

(aq) + e- Ag (s)

Reaction with higher E0

value / ∆ G0

negative

(ii) Molar conductivity of a solution at infinite dilution or when concentration approaches

zero

Number of ions per unit volume decreases

½

½

½

½

8. Elements which have partially filled d-orbital in its ground states or any one of its oxidation

states.

1) Variable oxidation states

2) Form coloured ion

Or any other two correct characteristics

1

½ +½

9. 1) Diamminedichloridoethylenediaminechromium(III) chloride

2) [Co(NH3)5(ONO)]2+

1+ 1

CHEMISTRY MARKING SCHEME

DELHI -2015

SET -56/1/3/D

Page 151: Chemistry Past Papers

10 (i)LiAlH4 / NaBH4 /H2, Pt

(ii)KMnO4 , KOH

1

1

11 (i)Hexamethylene diamine NH2 (CH2)6 NH2 and

adipic acid HOOC- (CH2)4- COOH

(ii)3 hydroxybutanoic acid CH3CH(OH)CH2COOH and

3 hydroxypentanoic acid CH3CH2CH(OH)CH2COOH

(iii)Chloroprene H2C=C(Cl)CH=CH2

IUPAC names are accepted

Note : ½ mark for name /s and ½ mark for structure / s

½

½

½

½

½

½

12 (i)CH3CH2CH3

(ii) C6H5COONa + CHI3

(iii)CH4

1

½, ½

1

13

13

(i) C6H5OH + NaOH C6H5ONa CH3X C6H5OCH3

Or

C6H5OH + Na C6H5ONa CH3X C6H5OCH3

(ii)CH3CH(OH)CH3 CrO3 or Cu/573K CH3COCH3 (i)CH3MgX (CH3)2C(OH)CH3

(ii)H2O

(iii)C6H5NH2 NaNO2 + HCl C6H5N2Cl H2O warm C6H5OH

273K

OR

a)

b)

1

1

1

½

½

1

1

Page 152: Chemistry Past Papers

(Acetyl chloride instead of acetic anhydride may be used)

14 (i)Maltose

(ii) fibrous proteins: parallel polypeptide chain , insoluble in water

Globular proteins: spherical shape, soluble in water, (or any 1 suitable difference)

(iii) Vitamin D

1

1

1

15 (i)Larger surface area, higher van der Waals’ forces , higher the boiling point

(ii)Rotation due to one enantiomer is cancelled by another enantiomer

(iii) - NO2 acts as Electron withdrawing group or –I effect

1

1

1

16.

∆Tf = i Kf m

∆Tf = i Kf mb x1000

Mb x ma

1.62 K = i x 4.9K kg mol-1

x 3.9 g x 1000

122 gmol-1

49 kg

i = 0.506

Or by any other correct method

As i<1 , therefore solute gets associated.

½

1

½

1

17 (i) Zinc being low boiling will distil first leaving behind impurities/ or on electrolysis the pure

metal gets deposited on cathode from anode.

(ii)Silica acts as flux to remove iron oxide which is an impurity as slag or FeO + SiO2 FeSiO3

(iii)Wrought iron

1

1

1

18 d = z x M

a3 NA

z = d a3 NA

M

z = 2.7 g cm-3

x 6.022 x1023

mol-1

x ( 4.05 x 10-8

cm)3

27 g mol-1

= 3.999 ≈ 4

Face centered cubic cell/ fcc

½

1

½

1

19 (i) 5f orbital electrons have poor shielding effect than 4f

(ii)due to d-d transition / or the energy of excitation of an electron from lower d orbital to higher

d-orbital lies in the visible region /presence of unpaired electrons in the d-orbital.

(iii) 2 MnO4- + 6 H

+ + 5 NO2

- 2 Mn

2+ + 3 H2O + 5 NO3

-

1

1

1

Page 153: Chemistry Past Papers

20 (i)

(ii)t2 g3 e g

1

(iii) sp3 , diamagnetic

1

1

½+ ½

21 The cell reaction : Fe(s) + 2H+ (aq) Fe

2+ (aq) + H2(g)

Eocell = E

oc - E

oa

= [0-(-0.44)]V=0.44V

Ecell = Ecell - 0.059 log [ Fe2+

]

2 [ H+]2

Ecell = 0.44 V - 0.059 log ( 0.001 )

2 ( 0.01 ) 2

= 0.44 V - 0.059 log ( 10 )

2

= 0.44 V - 0.0295 V

=≈ 0.410 V

1

1

1

22 (i) mutual coagulation

(ii)strong interaction between dispersed phase and dispersion medium or solvated layer

(iii)CO acts as a poison for catalyst or iron

1

1

1

23 (i) Concern for students health, Application of knowledge of chemistry to daily life,

empathy , caring or any other

(ii)Through posters, nukkad natak in community, social media, play in assembly or any other

(iii)Tranquilizers are drugs used for treatment of stress or mild and severe mental disorders .. Eg:

equanil (or any other suitable example)

(iv) Aspartame is unstable at cooking temperature.

½, ½

1

½ , ½

1

o

Page 154: Chemistry Past Papers

24

24.

(a)

k = 2.303 log [ A0 ]

t [A]

k = 2.303 log 0.60

30 0.30

k = 2.303 x 0.301 = 0.023 s-1

30

k = 2.303 log 0.60

60 0.15

k = 2.303 x 0.6021 = 0.023 s-1

60

As k is constant in both the readings, hence it is a pseudofirst order reaction.

ii)

Rate = - Δ[R]/Δt

= -[0.15-0.30]

60-30

= 0.005 mol L-1

s-1

OR

a) (i) Rate will increase 4 times of the actual rate of reaction.

(ii) Second order reaction

b) t

1/2 = 0.693

k

30min =

0.693

k

1

½

½

1

½

½

1

1+1

½

Page 155: Chemistry Past Papers

k = 0.0231min

-1

k = 2.303 log [ A0 ]

t [A]

t = 2.303 log 100

0.0231 10

t = 2.303 min

0.0231

t = 99.7min

½

½

½

1

25

25

(a) (i) Due to decrease in bond dissociation enthalpy from HF to HI , there is an increase in acidic

character observed.

(ii)Oxygen exists as diatomic O2 molecule while sulphur as polyatomic S8

(iii)Due to non availability of d orbitals

(b)

OR

(i) White Phosphorus because it is less stable due to angular strain

(ii)Nitrogen oxides emitted by supersonic jet planes are responsible for depletion of ozone layer.

Or NO+O3 NO2+ O2

(iii)due to small size of F, large inter electronic repulsion / electron- electron repulsion among the

lone pairs of fluorine

1

1

1

1

1

½ , ½

1

1

Page 156: Chemistry Past Papers

(iv)Helium

(v) XeF2 + PF5 [XeF]+ [PF6]

- 1

1

26.

26.

A = B = C = D = E =

OR

O

a. i)

ii) iii)

b. ( CH3)3N < C2H5NH2 < C2H5OH

c. By Hinsberg test secondary amines ( CH3)2NH shows ppt formation which is insoluble

KOH

while

in tertiary amines ( CH3)3N do not react with benzene sulphonyl choride

1x5=

5

1

1

1

1

1

Page 157: Chemistry Past Papers

56/2/2/F 1 P.T.O.

narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð >na Adí` bIo§ & Candidates must write the Code on the

title page of the answer-book.

Series SSO/2 H$moS> Z§.

Code No.

amob Z§. Roll No.

agm`Z dkmZ (g¡ÕmpÝVH$)

CHEMISTRY (Theory)

ZYm©[aV g_` : 3 KÊQ>o AYH$V_ A§H$ : 70

Time allowed : 3 hours Maximum Marks : 70

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _o§ _wÐV n¥ð> 15 h¢ &

àíZ-nÌ _| XmhZo hmW H$s Amoa XE JE H$moS >Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na bI| &

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _| >26 àíZ h¢ & H¥$n`m àíZ H$m CÎma bIZm ewê$ H$aZo go nhbo, àíZ H$m H«$_m§H$ Adí` bI| &

Bg àíZ-nÌ H$mo n‹T>Zo Ho$ bE 15 _ZQ >H$m g_` X`m J`m h¡ & àíZ-nÌ H$m dVaU nydm©• _| 10.15 ~Oo H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg AdY Ho$ Xm¡amZ do CÎma-nwpñVH$m na H$moB© CÎma Zht bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

Please check that this question paper contains 26 questions.

Please write down the Serial Number of the question before

attempting it.

15 minute time has been allotted to read this question paper. The question

paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

56/2/2/F

SET-2

Page 158: Chemistry Past Papers

56/2/2/F 2

gm_mÝ` ZXe :

(i) g^r àíZ AZdm`© h¢ &

(ii) àíZ g§»`m 1 go 5 VH$ AV bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 1 A§H$ h¡ &

(iii) àíZ g§»`m 6 go 10 VH$ bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 2 A§H$ h¡§ &

(iv) àíZ g§»`m 11 go 22 VH$ ^r bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 3 A§H$ h¢ &

(v) àíZ g§»`m 23 _yë`mYm[aV àíZ h¡ Am¡a BgHo$ bE 4 A§H$ h¢ &

(vi) àíZ g§»`m 24 go 26 VH$ XrK©-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 5 A§H$ h¢ &

(vii) `X Amdí`H$Vm hmo, Vmo bm°J Q>o~bm| H$m à`moJ H$a| & H¡$ëHw$boQ>am| Ho$ Cn`moJ H$s AZw_V Zht h¡ &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 5 are very short answer questions and carry

1 mark each.

(iii) Questions number 6 to 10 are short answer questions and carry 2 marks

each.

(iv) Questions number 11 to 22 are also short answer questions and carry

3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Questions number 24 to 26 are long answer questions and carry 5 marks

each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. XE JE `m¡JH$ H$m AmB©. y.nr.E.gr. Zm_ bIE : 1

HO CH2 CH = C CH3

CH3

Page 159: Chemistry Past Papers

56/2/2/F 3 P.T.O.

Write the IUPAC name of the given compound :

HO CH2 CH = C CH3

CH3

2. ^m¡VH$emofU CËH«$_Ur` h¡ O~H$ amgm`ZH$emofU AZwËH«$_Ur` hmoVm h¡ & Š`m| ? 1

Physisorption is reversible while chemisorption is irreversible. Why ?

3. ZåZbIV `w½_ _| H$m¡Z SN2 A^H«$`m AYH$ Vrd«Vm go H$aoJm Am¡a Š`m| ? 1

CH3 CH2 Br Am¡a CH3 CH2 I

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 CH2 Br and CH3 CH2 I

4. gm_mÝ` Vmn_mZ na gë\$a H$m H$m¡Z-gm Anaê$n (EbmoQ´>mon) D$î_r` ê$n go ñWm`r h¡ ? 1

Which allotrope of sulphur is thermally stable at room temperature ?

5. Cg `m¡JH$ H$m gyÌ Š`m h¡ Og_| VÎd Y ccp OmbH$ ~ZmVm h¡ Am¡a X Ho$ na_mUw

AîQ>\$bH$s` [a>º$ H$m 2/3dm± ^mJ KoaVo h¢ ? 1

What is the formula of a compound in which the element Y forms ccp

lattice and atoms of X occupy 2/3rd of octahedral voids ?

6. ZåZbIV A^H«$`mAm| _| à`moJ AmZo dmbo A^H$maH$m| Ho$ Zm_ XrOE : 2

(i) CH3 CHO ?

CH3 CH CH3

|

OH

(ii) CH3 COOH ?

CH3 COCl

Name the reagents used in the following reactions :

(i) CH3 CHO ?

CH3 CH CH3 |

OH

(ii) CH3 COOH ?

CH3 COCl

Page 160: Chemistry Past Papers

56/2/2/F 4

7. (a) Obr` H$m°na(II) ŠbmoamBS> db`Z Ho$ dÚwV ²-AnKQ>Z Ho$ Xm¡amZ H¡$WmoS> na ZåZbIV A^H«$`mE± hmoVr h¢ :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

CZHo$ _mZH$ AnM`Z BboŠQ´>moS> d^d (E0) Ho$ _mZm| Ho$ AmYma na H¡$WmoS> na H$g

A^H«$`m H$s g§^mdZm (gwg§JVVm) h¡ Am¡a Š`m| ?

(b) Am`Zm| Ho$ ñdV§Ì A^J_Z Ho$ H$mobamD$e Z`_ H$m H$WZ H$sOE & BgH$m EH$ AZwà`moJ bIE & 2

(a) Following reactions occur at cathode during the electrolysis of

aqueous copper(II) chloride solution :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

On the basis of their standard reduction electrode potential (E0)

values, which reaction is feasible at the cathode and why ?

(b) State Kohlrausch law of independent migration of ions. Write its

one application.

8. amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ go Š`m VmËn`© h¡ ? EH$ CXmhaU XrOE & G$UmË_H$ dMbZ Ho$ bE ∆mixH H$m Š`m M• hmoVm h¡ ? 2>

AWdm

EµOAmoQ´>mon H$mo n[a^mfV H$sOE & amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ Ûmam ~ZZo dmbm EµOAmoQ´>mon H$g àH$ma H$m hmoVm h¡ ? EH$ CXmhaU XrOE & 2

Page 161: Chemistry Past Papers

56/2/2/F 5 P.T.O.

What is meant by negative deviation from Raoult’s law ? Give an

example. What is the sign of mixH for negative deviation ?

OR

Define azeotropes. What type of azeotrope is formed by negative

deviation from Raoult’s law ? Give an example.

9. g§H«$_U VÎd Š`m| n[adVu CnM`Z AdñWmAm§o H$mo àXe©V H$aVo h¢ ? 3d loUr _| (Sc go Zn)

H$m¡Z-gm VÎd gdm©YH$ CnM`Z AdñWmE± Xem©Vm h¡ Am¡a Š`m| ? 2

Why do transition elements show variable oxidation states ? In 3d series

(Sc to Zn), which element shows the maximum number of oxidation

states and why ?

10. (i) ZåZbIV H$m°åßboŠg H$m AmB©.`y.nr.E.gr. Zm_ bIE :

[Cr (en)3]Cl3

(ii) ZåZbIV H$m°åßboŠg H$m gyÌ bIE :

nmoQ>¡e`_ Q´>mB© Am°Šgb¡Q>mo H«$mo_oQ>(III) 2

(i) Write down the IUPAC name of the following complex :

[Cr (en)3]Cl3

(ii) Write the formula for the following complex :

Potassium tri oxalato chromate(III)

11. 25C na ZåZ gob H$m dÚwV²-dmhH$ ~b (B©.E_.E\$.) n[aH$bV H$sOE : 3

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

Calculate the emf of the following cell at 25C :

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

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56/2/2/F 6

12. ZåZbIV AdbmoH$Zm| Ho$ bE H$maUm| H$mo XrOE : 3

(i) g_wÐr Ob Am¡a ZXr H$m Ob Ohm± _bVo h¢ dhm± EH$ S>oëQ>m ~Z OmVm h¡ &

(ii) MmaH$mob H$s gVh na N2 J¡g H$s Anojm NH3 J¡g AYH$ erK«Vm go AYemofV hmoVr h¡ &

(iii) MyU© H$E hþE nXmW© AYH$ à^mdembr AYemofH$ hmoVo h¢ &

Give reasons for the following observations :

(i) A delta is formed at the meeting point of sea water and river

water.

(ii) NH3 gas adsorbs more readily than N2 gas on the surface of

charcoal.

(iii) Powdered substances are more effective adsorbents.

13. (i) H$m°åßboŠg [Pt(en)2Cl2]2+ Ho$ Á`m_Vr` g_md`dm| H$mo AmaoIV H$sOE &

(ii) H«$ñQ>b \$sëS> gÕmÝV Ho$ AmYma na `X ∆o > P h¡, Vmo d4 Am`Z H$m BboŠQ´>m°ZH$ dÝ`mg bIE &

(iii) H$m°åßboŠg [Ni(CN)4]2 H$m g§H$aU àH$ma Am¡a Mwå~H$s` ì`dhma bIE & (Ni H$m na_mUw H«$_m§H$ = 28) 3

(i) Draw the geometrical isomers of complex [Pt(en)2Cl2]2+.

(ii) On the basis of crystal field theory, write the electronic

configuration for d4 ion, if o P.

(iii) Write the hybridization type and magnetic behaviour of the

complex [Ni(CN)4]2. (Atomic number of Ni = 28)

14. (a) ZåZbIV H$mo Amn H$maU XoVo hþE H¡$go g_PmE±Jo :

(i) Mn H$m CƒV_ âbwAmoamBS> MnF4 h¡ O~H$ CƒV_ Am°ŠgmBS> Mn2O7

h¡ &

(ii) g§H«$_U YmVwE± Am¡a CZHo$ `m¡JH$ CËàoaH$ JwUY_© Xem©Vo h¢ &

(b) ZåZbIV g_rH$aU H$mo nyU© H$sOE :

3–2

4MnO + 4H+ 3

Page 163: Chemistry Past Papers

56/2/2/F 7 P.T.O.

(a) How would you account for the following :

(i) Highest fluoride of Mn is MnF4 whereas the highest oxide is

Mn2O7.

(ii) Transition metals and their compounds show catalytic

properties.

(b) Complete the following equation :

3–2

4MnO + 4H+

15. ZåZbIV A^H«$`mAm| Ho$ CËnmXm| H$s àmJwº$ H$sOE : 3

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

Predict the products of the following reactions :

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

16. EH$ VÎd X (_moba Ðì`_mZ = 60 g mol1) H$m KZËd 6·23 g cm3 h¡ & `X `yZQ> gob Ho$ H$moa H$s bå~mB© 4 × 108 cm h¡, Vmo Š`y~H$ `yZQ> gob Ho$ àH$ma H$s Š`m nhMmZ hmoJr ? 3

An element X (molar mass = 60 g mol1) has a density of 6.23 g cm3.

Identify the type of cubic unit cell, if the edge length of the unit cell is

4 × 108 cm.

Page 164: Chemistry Past Papers

56/2/2/F 8

17. 37·2 g Ob _| NaCl (_mob Ðì`_mZ = 58·5 g mol1) H$s H$VZr _mÌm KwbmB© OmE H$ h_m§H$ 2°C KQ> OmE, `h _mZVo hþE H$ NaCl nyU© ê$n go dKQ>V hmoVm h¡ ?

(Kf Ob Ho$ bE = 1·86 K kg mol1) 3

Calculate the mass of NaCl (molar mass = 58·5 g mol1) to be dissolved in

37·2 g of water to lower the freezing point by 2C, assuming that NaCl

undergoes complete dissociation. (Kf for water = 1·86 K kg mol1)

18. ZåZbIV ~hþbH$m| Ho$ EH$bH$m| Ho$ Zm_ Am¡a CZH$s g§aMZmE± bIE : 3

(i) Q>oarbrZ

(ii) ~¡Ho$bmBQ>

(iii) ~wZm-S

Write the names and structures of the monomers of the following

polymers :

(i) Terylene

(ii) Bakelite

(iii) Buna-S

19. (a) EpëH$b h¡bmBS>| Ob _| KwbZerb Zht h¢ & Š`m| ?

(b) ã`wQ>¡Z-1-Am°b àH$meH$s` ZpîH«$` (Y«wdU AKyU©H$) h¡ naÝVw ã`wQ>¡Z-2-Am°b

àH$meH$s` gH«$` (Y«wdU KyU©H$) h¡ & Š`m| ?

(c) `Ún ŠbmoarZ BboŠQ´>m°Z H$mo AmH$f©V H$aZo dmbm J«wn h¡ \$a ^r `h BboŠQ´>m°ZñZohr Eamo_¡Q>H$ àVñWmnZ A^H«$`mAm| _| Am°Wm- VWm n¡am- ZXeH$ h¡ & Š`m| ? 3

(a) Why are alkyl halides insoluble in water ?

(b) Why is Butan-1-ol optically inactive but Butan-2-ol is optically

active ?

(c) Although chlorine is an electron withdrawing group, yet it is

ortho-, para- directing in electrophilic aromatic substitution

reactions. Why ?

Page 165: Chemistry Past Papers

56/2/2/F 9 P.T.O.

20. ZåZbIV H$m ê$nm§VaU Amn H¡$go H$a|Jo : 3

(i) ~oݵOmoBH$ EgS> H$mo ~oݵO¡pëS>hmBS> _|

(ii) EWmB©Z H$mo EW¡Z¡b _|

(iii) EogrQ>H$ EgS> H$mo _rWoZ _|

AWdm

ZåZbIV A^H«$`mAm| go gå~pÝYV g_rH$aUm| H$mo bIE : 3

(i) ñQ>r\$Z A^H«$`m

(ii) dmoë\$-H$íZa AnM`Z

(iii) EQ>mS>© A^H«$`m How do you convert the following :

(i) Benzoic acid to Benzaldehyde

(ii) Ethyne to Ethanal

(iii) Acetic acid to Methane

OR

Write the equations involved in the following reactions :

(i) Stephen reaction

(ii) Wolff-Kishner reduction

(iii) Etard reaction

21. (i) ZåZbIV _§o H$m¡Z _moZmog¡Ho$amBS> h¡ : ñQ>mM©, _mëQ>mog, \«$ŠQ>mog, gobwbmog

(ii) Aåbr` Eo_Zmo EogS>m| Am¡a jmar` Eo_Zmo EogS>m| Ho$ ~rM$ Š`m A§Va hmoVm h¡ ?

(iii) Cg dQ>m_Z H$m Zm_ bIE OgH$s H$_r Ho$ H$maU _gy‹S>m| _| IyZ AmZo bJVm h¡ & 3

(i) Which one of the following is a monosaccharide :

starch, maltose, fructose, cellulose

(ii) What is the difference between acidic amino acids and basic amino

acids ?

(iii) Write the name of the vitamin whose deficiency causes bleeding of

gums.

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56/2/2/F 10

22. (i) ZH$b Ho$ n[aîH$aU _| H$m_ AmZo dmbr dY Ho$ nrN>o Omo gÕmÝV hmoVm h¡ CgH$m

C„oI H$sOE &

(ii) gmoZo Ho$ ZîH$f©U _| VZw NaCN H$s Š`m ^y_H$m hmoVr h¡ ?

(iii) ‘H$m°na _¡Q>o’ Š`m hmoVm h¡ ? 3

(i) Indicate the principle behind the method used for the refining of

Nickel.

(ii) What is the role of dilute NaCN in the extraction of gold ?

(iii) What is ‘copper matte’ ?

23. ~ƒm| _| _Yw_oh Am¡a CXmgr Ho$ ~‹T>Vo Ho$gm| H$mo XoIZo Ho$ ~mX EH$ àgÕ ñHy$b Ho$ qàgnb

lr Mmon ‹S>m Zo EH$ go_Zma H$m Am`moOZ H$`m Og_| CÝhm|Zo ~ƒm| Ho$ A^^mdH$m| VWm AÝ`

ñHy$bm| Ho$ qàgnbm| H$mo Am_§ÌV H$`m & CÝhm|Zo ñHy$bm| _| g ‹S>o hþE ^moÁ` nXmWm] (O§H$ \y$S>) na àV~§Y bJmZo H$m ZU©` b`m, gmW hr `h ZU©` b`m H$ ñHy$bm| _| ñdmñÏ`dY©H$

nXmW© O¡go gyn, bñgr, XÿY AmX H¢$Q>rZm| _| CnbãY H$amB© OmE± & CÝhm|Zo `h ^r ZU©`

b`m H$ àmV:H$mbrZ Egoå~br Ho$ g_` ~ƒm| H$mo àVXZ AmYo K§Q>o H$s emar[aH$ H$gaV ^r H$amB© OmE & N>: _mh níMmV² lr Mmon ‹S>m Zo ~ƒm| Ho$ ñdmñÏ` H$m AYH$V_ dÚmb`m| _|

nwZ: ZarjU H$adm`m Am¡a ~ƒm| Ho$ ñdmñÏ` _| AZ wn_ gwYma nm`m J`m &

Cn w©º$ àH$aU H$mo n‹T>Zo Ho$ ~mX, ZåZbIV àíZm| Ho$ CÎma XrOE : 4 (i) lr Mmon ‹S>m Ûmam H$Z _yë`m| (H$_-go-H$_ Xmo) H$mo Xem©`m J`m h¡ ?

(ii) EH$ dÚmWu Ho$ ê$n _|, Amn Bg df` _| H¡$go OmJê$H$Vm \¡$bmE±Jo ?

(iii) AdZ_Z-damoYr S´>J ~Zm S>m°ŠQ>a H$s gbmh Ho$ Š`m| Zht boZ o MmhE ?

(iv) H¥$Ì_ _YwaH$ Ho$ Xmo CXmhaU XrOE &

Seeing the growing cases of diabetes and depression among children,

Mr. Chopra, the principal of one reputed school organized a seminar in

which he invited parents and principals. They all resolved this issue by

strictly banning the junk food in schools and by introducing healthy

snacks and drinks like soup, lassi, milk etc. in school canteens. They also

decided to make compulsory half an hour physical activities for the

students in the morning assembly daily. After six months,

Mr. Chopra conducted the health survey in most of the schools and

discovered a tremendous improvement in the health of students.

Page 167: Chemistry Past Papers

56/2/2/F 11 P.T.O.

After reading the above passage, answer the following questions :

(i) What are the values (at least two) displayed by Mr. Chopra ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) Why should antidepressant drugs not be taken without consulting

a doctor ?

(iv) Give two examples of artificial sweeteners.

24. (a) ZåZbIV Ho$ H$maU XoVo hþE ñnîQ> H$sOE :

(i)

4NH _| Omo Am~ÝY H$moU h¡ dh NH3 Ho$ H$moU go CƒVa h¡ &

(ii) H2O H$s Anojm H2S H$m ŠdWZm§H$ Ý`yZVa h¡ &

(iii) AnM`Z ì`dhma SO2 go TeO2 H$s Amoa KQ>Vm h¡ &

(b) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) H4P2O7 (nm`amo\$m°ñ\$mo[aH$ EogS>)

(ii) XeF2 5

AWdm

(a) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) XeF4

(ii) H2S2O7

(b) ZåZbIV Ho$ H$maU XrOE :

(i) HCl go A^H«$`m go Am`aZ FeCl2 ~ZmVm h¡ Z H$s FeCl3.

(ii) HClO H$s Anojm HClO4 à~bVa Aåb h¡ &

(iii) dJ© 15 Ho$ g^r hmBS´>mBS>m| _| BiH3 à~bV_ AnMm`H$ h¡ & 5

(a) Account for the following :

(i) Bond angle in

4NH is higher than NH3.

(ii) H2S has lower boiling point than H2O.

(iii) Reducing character decreases from SO2 to TeO2.

Page 168: Chemistry Past Papers

56/2/2/F 12

(b) Draw the structures of the following :

(i) H4P2O7 (Pyrophosphoric acid)

(ii) XeF2

OR

(a) Draw the structures of the following :

(i) XeF4

(ii) H2S2O7

(b) Account for the following :

(i) Iron on reaction with HCl forms FeCl2 and not FeCl3.

(ii) HClO4 is a stronger acid than HClO.

(iii) BiH3 is the strongest reducing agent amongst all the

hydrides of group 15.

25. (a) àË`oH$ Ho$ bE Cn wº$ CXmhaU XoVo hþE ZåZbIV A^H«$`mAm| H$mo àXe©V H$sOE : (i) A_moZrH$aU (ii) H$pßb¨J (`w½_Z) A^H«$`m (iii) Eo_rZm| H$m EogrQ>brH$aU

(b) àmW_H$ (àmB_ar), ÛVr`H$ (goH$ÊS>ar) Am¡a V¥Vr`H$ (Q>e©`ar) E_rZm| H$s nhMmZ H$aZo Ho$ bE hÝg~J© dY H$m dU©Z H$sOE & gå~Õ A^H«$`mAm| Ho$ amgm`ZH$ g_rH$aUm| H$mo ^r bIE & 5

AWdm

(a) O~ ~oݵOrZ S>mBEµOmoZ`_ ŠbmoamBS> (C6 H5–

2ClN ) ZåZbIV A^H$maH$m| go

A^H«$`m H$aVm h¡, V~ àmßV _w»` CËnmXm| H$s g§aMZmE± bIE :

(i) HBF4 /

(ii) Cu / HBr

Page 169: Chemistry Past Papers

56/2/2/F 13 P.T.O.

(b) ZåZbIV A^H«$`mAm| _| A, B Am¡a C H$s g§aMZmE± bIE :

5

(a) Illustrate the following reactions giving suitable example in each

case :

(i) Ammonolysis

(ii) Coupling reaction

(iii) Acetylation of amines

(b) Describe Hinsberg method for the identification of primary,

secondary and tertiary amines. Also write the chemical equations

of the reactions involved.

OR

(a) Write the structures of main products when benzene diazonium

chloride (C6 H5–

2ClN ) reacts with the following reagents :

(i) HBF4 /

(ii) Cu / HBr

(b) Write the structures of A, B and C in the following reactions :

Page 170: Chemistry Past Papers

56/2/2/F 14

26. (a) ZåZbIV nXm| H$mo n[a^mfV H$sOE :

(i) gH«$`U D$Om©

(ii) Xa pñWam§H$

(b) 25% d`moOZ Ho$ bE EH$ àW_ H$moQ> H$s A^H«$`m 10 _ZQ> boVr h¡ & A^H«$`m Ho$ bE t

1/2 H$m n[aH$bZ H$sOE >& 5

(X`m J`m : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

AWdm

(a) EH$ amgm`ZH$ A^H«$`m R P Ho$ bE gm§ÐU _| n[adV©Z ln [R] vs. g_` (s) ZrMo ßbm°Q> _| X`m J`m h¡ :

ln [R]

t (s)

(i) A^H«$`m H$s H$moQ> H$s àmJwº$ H$sOE &

(ii) dH«$ H$m T>bmZ Š`m h¡ ?

(iii) A^H«$`m Ho$ bE Xa pñWam§H$ H$s `yZQ> bIE &

(b) Xem©BE H$ 99% nyU© hmoZo _| Omo g_` bJVm h¡ dh Cg g_` H$m XwJwZm h¡ Omo

A^H«$`m Ho$ 90% nyU© hmoZo _| bJVm h¡ & 5

(a) Define the following terms :

(i) Activation energy

(ii) Rate constant

(b) A first order reaction takes 10 minutes for 25% decomposition.

Calculate t1/2

for the reaction.

(Given : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

OR

Page 171: Chemistry Past Papers

56/2/2/F 15 P.T.O.

(a) For a chemical reaction R P, the variation in the concentration,

ln [R] vs. time (s) plot is given as

ln [R]

t (s)

(i) Predict the order of the reaction.

(ii) What is the slope of the curve ?

(iii) Write the unit of rate constant for this reaction.

(b) Show that the time required for 99% completion is double of the

time required for the completion of 90% reaction.

Page 172: Chemistry Past Papers

1

Qn Value points Marks

1 3-Methylbut-2-en-1-ol 1

2 Because of weak van der Waals’ forces in physisorption whereas there are strong chemical

forces in chemisorption.

1

3 CH3CH2I , because I is a better leaving group. ½ , ½

4 Rhombic sulphur 1

5 X2Y3 1

6 (i) CH3MgBr/ H3O+

(ii) PCl5/ PCl3 / SOCl2

1

1

7 a) Cu2+

(aq) + 2 e Cu(s) because of high E0 value/ more negative ∆G

b) It states that limiting molar conductivity of an electrolyte is equal to the sum of the individual

contributions of cations and anions of the electrolyte.

It is used to calculate the Ʌm0 for weak electrolyte / It is used to calculate α and Kc

(Any one application)

½ , ½

1

1

8

8

When solute- solvent interaction is stronger than pure solvent or solute interaction.

Eg: chloroform and acetone (or any other correct eg)

∆mixH= negative

OR

Azeotropes –binary mixtures having same composition in liquid and vapour phase and boil at

constant temperature / is a liquid mixture which distills at constant temperature without

undergoing change in composition

Maximum boiling azeotropes

eg: HNO3 (68%) and H2O(32%) (or any other correct example)

1

½

½

1

½

½

9 a) Due to presence of unpaired d-electrons/ comparable energies of 3d and 4s orbitals.

b) Mn , due to involvement of 4s and 3d electrons/ presence of maximum unpaired d-

electrons.

1

½ ,½

CHEMISTRY MARKING SCHEME 2015

SET -56/2/2 F

Page 173: Chemistry Past Papers

2

10 i) tris-(ethane-1,2-diamine)chromium(III) chloride

ii) K3[ Cr(C2O4)3]

1

1

11 E cell = E

0 cell –

log

E cell = 0.76 V -

V log

( )

E cell = 0.76 – 0.0295 V log 10

= 0.7305 V

1

1

1

12 i) Due to coagulation of colloidal clay particles.

ii) Because NH3 is easily liquefiable than N2 due to its larger molecular size.

iii) Because of more surface area.

1

1

1

13

i)

cis- isomer trans-isomer

ii) t2g4

iii) dsp 2

, diamagnetic

1

1

½ , ½

14 i) Because oxygen stabilizes Mn more than F due to multiple bonding

ii) Because of their ability to show variable oxidation state(or any other correct reason)

iii) 3MnO42-

+ 4H+ 2MnO4

- + MnO2 + 2H2O

1

1

1

15 i) CH3CH2CH2OH

ii)

iii) CH3CHO

1

1

1

Page 174: Chemistry Past Papers

3

16 d=

6.23 g cm-3

=

( )

z=4

fcc

½

½

1

1

17 ∆ Tf = i. Kf m

= i Kf wB x 1000

MB x wA

2K= 2 x 1.86K kg/mol x wB x 1000

58.5 g/mol x 37.2 g

wB = 1.17g

1

1

1

18

i)

ii)

Phenol and formaldehyde

iii)

(Note: half mark for structure/s and half mark for name/s)

1

1

1

19 a) Because they are unable to form H-bonds with water molecules.

b) Because of the presence of chiral carbon in butan-2-ol.

c) Due to dominating +R effect

1

1

1

20

i) C6H5COOH PCl5 C6H5COCl H2/Pd C6H5CHO

BaSO4

ii) CH≡CH + H2O Hg2+

/H2SO4 CH3CHO

iii) CH3COOH NaOH

CH3COONa NaOH + CaO , heat

CH4

OR

1

1

1

Page 175: Chemistry Past Papers

4

20

i)

ii)

iii)

1

1

1

21 i) Fructose

ii) Acidic amino acid has more number of acidic carboxylic group than basic amino

group whereas basic amino acid has more number of basic amino group.

iii) Vitamin C

1

1

1

22 a) Impure Ni reacts with CO to form volatile Ni(CO)4 which when heated at higher

temperature decomposes to give pure Ni.

b) NaCN acts as a leaching agent to form a soluble complex with gold.

c) It is a mixture of Cu2S and FeS

1

1

1

23 a) Concern for students health, Application of knowledge of chemistry to daily life, empathy

, caring or any other

b) Through posters, nukkad natak in community, social media, play in assembly (or any other

relevant answer)

c) Wrong choice and overdose may be harmful

d) Aspartame, saccharin (or any other correct example)

½ , ½

1

1

½+ ½

24

a) i)Because of lone pair in NH3 , lone pair- bond pair repulsion decreases the bond angle

ii)Because of absence of H-bonding in H2S

iii)Because stability of +4 oxidation state increases from SO2 to TeO2

b)

1

1

1

1,1

Page 176: Chemistry Past Papers

5

24

OR

a)

b)i)Because iron on reaction with HCl produces H2(g) which prevents the formation of FeCl2 to

FeCl3 / Because HCl is a weak oxidising agent.

ii) Because of higher oxidation state of chlorine in HClO4

iii) Because of lower dissociation enthalpy of Bi-H bond.

1,1

1

1

1

25

a) i)ammonolysis

ii)

(any one)

1

1

Page 177: Chemistry Past Papers

6

25

iii) (or any other correct reaction)

b)reaction of primary amine

(soluble in alkali)

Reaction of secondary amine

(insoluble in alkali)

Tertiary amine doesn’t react

OR

a) i)

ii)

1

1

1

1

1

½,½,

½

Page 178: Chemistry Past Papers

7

b) i) A- B- C-

ii) A- CH3CN B- CH3CH2NH2 C- CH3CH2OH

½ ,½,

½

26

26

a)i) Activation energy- Extra energy required by reactants to form activated complex.

ii) Rate constant- rate of reaction when the concentration of reactant is unity.

b)

k= 2.303 log [ A0 ]

t [A]

k = 2.303 log 100

10 min 75

k = 2.303 x 0.125

10 min

k = 0.02879 min-1

t1/2 =

=

t1/2 = 24.07min

OR

a) i)First order ii) -k iii) s-1

b)

t =

log

t99% =

log

t =

x 2

1

1

½

½

1

1

1,1,1

½

Page 179: Chemistry Past Papers

8

t90% =

log

=

t99% = 2 x t90%

½

1

Page 180: Chemistry Past Papers

56/1/2/D 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸üÃÖÖµÖ®Ö ×¾Ö–ÖÖ®Ö (ÃÖî üÖ×®ŸÖÛú) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÞ™êüü] [†×¬ÖÛúŸÖ´Ö †ÓÛúú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µÖ ×®Ö¤ìü¿Ö :

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(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïü …

(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú»ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1 ÛúÖê›ü ®ÖÓ. Code No.

56/1/2/D

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 12 Æïü …

• ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë …

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü …

• Ûéú¯ÖµÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢Ö¸ü ×»ÖÜÖ®ÖÖ ¿Öãºþ Ûú¸ü®Öê ÃÖê ¯ÖÆü»Öê, ¯ÖÏ¿®Ö ÛúÖ ÛÎú´ÖÖÓÛú †¾Ö¿µÖ ×»ÖÜÖë …

• ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê ×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will only read the

question paper and will not write any answer on the answer-book during this period.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 2

Page 181: Chemistry Past Papers

56/1/2/D 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. no. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. no. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. no. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. no. 23 is a value based question and carry 4 marks.

(vi) Q. no. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculators is not allowed.

1. ×®Ö´®Ö µÖãÝ´Ö ´Öë ÛúÖî®Ö SN2 †×³Ö×ÛÎúµÖÖ †×¬ÖÛú ŸÖß¾ÖΟÖÖ ÃÖê Ûú êüÝÖÖ †Öî ü ŒµÖÖë ? 1

CH3 – CH2 – Br ŸÖ£ÖÖ CH3 –

C|

C|

B

H3

r

CH3

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 – CH2 – Br and CH3 –

C|

C|

B

H3

r

CH3

2. BaCl2 †Öî ü KCl ´Öë ÃÖê ÛúÖî®Ö ŠúÞÖÖŸ´ÖÛú “ÖÖ•ÖÔ ¾ÖÖ»Öê ÛúÖê»ÖÖ‡›üß ÃÖÖò»Ö ÛúÖ ÃÛÓú¤ü®Ö †×¬ÖÛú ¯ÖϳÖÖ¾Ö¿ÖÖ»Öß œÓüÝÖ ÃÖê

Ûú¸êüÝÖÖ ? ÛúÖ¸üÞÖ ¤üßו֋ … 1

Out of BaCl2 and KCl, which one is more effective in causing coagulation of a

negatively charged colloidal Sol ? Give reason.

3. ˆÃÖ µÖÖî×ÝÖÛú ÛúÖ ÃÖæ¡Ö ŒµÖÖ ÆüÖêÝÖÖ ×•ÖÃÖ´Öë Y ŸÖ¢¾Ö ccp •ÖÖ»ÖÛú ²Ö®ÖÖŸÖÖ Æîü †Öî ü X “ÖŸÖã±ú»ÖÛúßµÖ ×¸ü׌ŸÖ ÛúÖ 1/3¾ÖÖÑ

³ÖÖÝÖ ‘Öê üŸÖÖ Æîü ? 1

What is the formula of a compound in which the element Y forms ccp lattice and

atoms of X occupy 1/3rd

of tetrahedral voids ?

Page 182: Chemistry Past Papers

56/1/2/D 3 [P.T.O.

4. H3PO4 Ûúß õÖÖ¸üÛúŸÖÖ ŒµÖÖ Æîü ? 1

What is the basicity of H3PO4 ?

5. פüµÖê ÝÖµÖê µÖÖî×ÝÖÛú ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö ×»Ö×ÜÖ‹ : 1

Write the IUPAC name of the given compound :

6. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ¯ÖϵÖãŒŸÖ †×³ÖÛúÖ¸üÛúÖë Ûêú ®ÖÖ´Ö ¤üßו֋ : 2

Name the reagents used in the following reactions :

(i) CH3 – CO – CH3 ?

→ CH3 – C|

O

H

H

– CH3

(ii) C6H5 – CH2 – CH3

?→ C6H5 – COO–K+

7. ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö Ûêú ×»ÖµÖê

∆mixH ÛúÖ ×“ÖÅ®Öü ŒµÖÖ Æîü ? 2

What is meant by positive deviations from Raoult’s law ? Give an example. What is

the sign of ∆mixH for positive deviation ?

†£Ö¾ÖÖ/OR

7. ‹×•ÖµÖÖê™ÒüÖê ÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ¯ÖÏÖ¯ŸÖ ‹×•ÖµÖÖê™ÒüÖê Ö ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ

ÆüÖêŸÖÖ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … 2

Define azeotropes. What type of azeotrope is formed by positive deviation from

Raoult’s law ? Give an example.

Page 183: Chemistry Past Papers

56/1/2/D 4

8. (a) ×ÃÖ»¾Ö¸ü Œ»ÖÖê üÖ‡›ü Ûêú •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö Ûêú ×¾ÖªãŸÖ †¯Ö‘Ö™ü®Ö ´Öë Ûîú£ÖÖê›ü ¯Ö¸ü ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

ˆ®ÖÛêú ´ÖÖ®ÖÛú †¯Ö“ÖµÖ®Ö ‡»ÖꌙÒüÖê›ü ×¾Ö³Ö¾Ö (E°) Ûêú ´ÖÖ®ÖÖë Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü Ûîú£ÖÖê›ü ¯Ö¸ü ×ÛúÃÖ †×³Ö×ÛÎúµÖÖ Ûúß

ÃÖÓ³ÖÖ¾Ö®ÖÖ Æîü †Öî ü ŒµÖÖë ?

(b) ÃÖß´ÖÖÓŸÖ ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾ÖªãŸÖË †¯Ö‘Ö™ËüµÖ Ûúß “ÖÖ»ÖÛúŸÖÖ ÃÖÖÓ¦üÞÖ Ûêú ‘Ö™ü®Öê Ûêú ÃÖÖ£Ö

ŒµÖÖë Ûú´Ö ÆüÖê®Öê »ÖÝÖŸÖß Æîü ? 2

(a) Following reactions occur at cathode during the electrolysis of aqueous silver

chloride solution :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

On the basis of their standard reduction electrode potential (E°) values, which

reaction is feasible at the cathode and why ?

(b) Define limiting molar conductivity. Why conductivity of an electrolyte solution

decreases with the decrease in concentration ?

9. ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾Ö ŒµÖÖ Æïü ? ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾ÖÖë Ûúß ¤üÖê ×¾Ö¿ÖêÂÖŸÖÖ†Öë ÛúÖê ×»Ö×ÜÖ‹ … 2

What are the transition elements ? Write two characteristics of the transition elements.

10. (i) ÛúÖò ¯»ÖêŒÃÖ [Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine) ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö

×»Ö×ÜÖµÖê …

(ii) ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖ ÛúÖ ÃÖæ¡Ö ×»Ö×ÜÖ‹ :

¯Öê®™üÖ‹ê ÖÖ‡®Ö®ÖÖ‡™ÒüÖ‡™üÖê-o-ÛúÖê²ÖÖ»™ü (III). 2

(i) Write down the IUPAC name of the following complex :

[Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine)

(ii) Write the formula for the following complex :

Pentaamminenitrito-o-Cobalt (III).

Page 184: Chemistry Past Papers

56/1/2/D 5 [P.T.O.

11. (i) ÛúÖò ¯»ÖêŒÃÖ [Pt(NH3)2Cl2] Ûêú •µÖÖ×´ÖŸÖßµÖ ÃÖ´ÖÖ¾ÖµÖ¾Ö ÛúÖê †Ö êü×ÜÖŸÖ Ûúßו֋ …

(ii) ×ÛÎúÙü»Ö ±úß»›ü ×ÃÖ¨üÖ®ŸÖ Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü µÖפü ∆o < P ÆüÖê ŸÖÖê d4 ÛúÖ ‡»ÖꌙÒüÖò®Ö ×¾Ö®µÖÖÃÖ ×»Ö×ÜÖ‹ …

(iii) ÛúÖò ¯»ÖêŒÃÖ [Ni(CO)4] ÛúÖ ÃÖÓÛú¸üÞÖ †Öî ü “Öã ²ÖÛúßµÖ ¯ÖÏÛéú×ŸÖ ×»Ö×ÜÖ‹ … (¯Ö.ÃÖÓ. Ni = 28) 3

(i) Draw the geometrical isomers of complex [Pt(NH3)2Cl2].

(ii) On the basis of crystal field theory, write the electronic configuration for d4 ion

if ∆o < P.

(iii) Write the hybridization and magnetic behaviour of the complex [Ni(CO)4].

(At.no. of Ni = 28)

12. ×®Ö´®Ö ÃÖê»Ö Ûúß 25 °C ¯Ö¸ü emf ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V 3

Calculate emf of the following cell at 25 °C :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V

13. ×®Ö´®Ö †¾Ö»ÖÖêÛú®ÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ¤üßו֋ :

(i) “Ö´ÖÔ¿ÖÖê¬Ö®Ö Ûêú ²ÖÖ¤ü “Ö´Ö›ÌüÖ ÃÖÜŸÖ ÆüÖê •ÖÖŸÖÖ Æîü …

(ii) ¦ü¾Ö ×¾Ö¸üÖê¬Öß ÃÖÖò»Ö Ûúß †¯ÖêõÖÖ ¦ü¾ÖîÖêÆüß ÃÖÖò»Ö †×¬ÖÛú ãÖÖµÖß ÆüÖêŸÖÖ Æîü …

(iii) •Ö²Ö Æîü²Ö¸ü ¯ÖÏÛÎú´Ö «üÖ¸üÖ †´ÖÖê×®ÖµÖÖ ²Ö®ÖÖµÖÖ •ÖÖŸÖÖ Æîü ŸÖ²Ö CO ÛúÖê ¤æü¸ü ¸üÜÖ®ÖÖ †Ö¾Ö¿µÖÛú ÆüÖêŸÖÖ Æîü … 3

Give reasons for the following observations :

(i) Leather gets hardened after tanning.

(ii) Lyophilic sol is more stable than lyophobic sol.

(iii) It is necessary to remove CO when ammonia is prepared by Haber’s process.

14. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö ¾Ö ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖµÖë ×»Ö×ÜÖ‹ :

(i) ®ÖÖµÖ»ÖÖò®Ö-6, 6

(ii) PHBV

(iii) ®Ö߆Öê ÖÏß®Ö 3

Write the names and structures of the monomers of the following polymers :

(i) Nylon-6, 6

(ii) PHBV

(iii) Neoprene

Page 185: Chemistry Past Papers

56/1/2/D 6

15. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ˆŸ¯ÖÖ¤üÖë Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

? 3

Predict the products of the following reactions :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

?

16. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ †Ö¯Ö ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ±úß®ÖÖò»Ö ÛúÖê ‹ê×®ÖÃÖÖò»Ö ´Öë

(ii) ¯ÖÏÖê Öî®Ö-2-†Öò»Ö ÛúÖê 2-´Öê×£Ö»Ö¯ÖÏÖê Öî®Ö-2-†Öò»Ö ´Öë

(iii) ‹ê×®Ö»Öß®Ö ÛúÖê ±úß®ÖÖò»Ö ´Öë 3

How do you convert the following :

(i) Phenol to anisole

(ii) Propan-2-ol to 2-methylpropan-2-ol

(iii) Aniline to phenol

†£Ö¾ÖÖ/OR

16. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ Ûúß ×ÛÎúµÖÖ-×¾Ö×¬Ö ÛúÖê ×»Ö×ÜÖ‹ :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) ÃÖî×»Ö×ÃÖ×»ÖÛú ‹ê×ÃÖ›ü Ûêú ‹êÃÖß™üß»ÖßÛú¸üÞÖ ÃÖê ÃÖ´²Ö¨ü ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ×»Ö×ÜÖ‹ … 3

(a) Write the mechanism of the following reaction :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) Write the equation involved in the acetylation of Salicylic acid.

Page 186: Chemistry Past Papers

56/1/2/D 7 [P.T.O.

17. (i) ×®Ö´®Ö ´Öë ÃÖê ÛúÖî®Ö ›üÖ‡ÔÃÖîÛêú¸üÖ‡›ü Æîü : ÙüÖ“ÖÔ, ´ÖÖ»™üÖêÃÖ, ±ÏúŒ™üÖêÃÖ, Ý»ÖæÛúÖêÃÖ ?

(ii) ¸êü¿Öê¤üÖ¸ü ¯ÖÏÖê™üß®Ö †Öî ü ÝÖÖê»ÖÖÛúÖ¸ü ¯ÖÏÖê™üß®Ö ´Öë ŒµÖÖ †ÓŸÖ¸ü Æîü ?

(iii) ²Ö““ÖÖë ´Öë ×ÛúÃÖ ×¾Ö™üÖ×´Ö®Ö Ûúß Ûú´Öß Ûêú ÛúÖ¸üÞÖ Æüøüß ´Öë Ûãúºþ¯ÖŸÖÖ ÆüÖê •ÖÖŸÖß Æîü ? 3

(i) Which one of the following is a disaccharide : Starch, Maltose, Fructose,

Glucose ?

(ii) What is the difference between fibrous protein and globular protein ?

(iii) Write the name of vitamin whose deficiency causes bone deformities in children.

18. ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤üßו֋ :

(a) t-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›üü Ûúß †¯ÖêõÖÖ n-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›ü ÛúÖ Œ¾Ö£Ö®ÖÖÓÛú ˆ““ÖŸÖ¸ü ÆüÖêŸÖÖ Æîü …

(b) ¸îüÃÖê×´ÖÛú ×´ÖÁÖÞÖ ¯ÖÏÛúÖ¿ÖÛúßµÖ ×®Ö×ÂÛÎúµÖ Æïü …

(c) ®ÖÖ׳ÖÛúîÖêÆüß ¯ÖÏןÖãÖÖ¯Ö®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ¯ÖÏ×ŸÖ Æîü»ÖÖꋸüß®ÖËÃÖ Ûúß ÃÖ×ÛÎúµÖŸÖÖ ²ÖœÌü •ÖÖŸÖß Æîü µÖפü o/p ¯ÖÖê•Öß¿Ö®Ö ¯Ö¸ü ®ÖÖ‡™ÒüÖê ÝÖÏã Ö (–NO2) ˆ¯Ö×Ã£ÖŸÖ ÆüÖê … 3

Give reasons :

(a) n-Butyl bromide has higher boiling point than t-butyl bromide.

(b) Racemic mixture is optically inactive.

(c) The presence of nitro group (–NO2) at o/p positions increases the reactivity of

haloarenes towards nucleophilic substitution reactions.

19. ²ÖꮕÖß®Ö Ûêú 49 g ´Öë ²ÖꮕÖÖê‡Ûú †´»Ö ÛúÖ 3.9 g ‘Öã»Ö®Öê ¯Ö¸ü ×Æü´ÖÖÓÛú ´Öë 1.62 K ÛúÖ †¾Ö®Ö´Ö®Ö ÆüÖê •ÖÖŸÖÖ Æîü … ¾Öî®™ü ÆüÖ±ú ÛúÖ¸üÛú ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ †Öî ü ×¾Ö»ÖêµÖ Ûêú þֳÖÖ¾Ö Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ (ÃÖÓÝÖã×ÞÖŸÖ µÖÖ ×¾Ö‘Ö×™üŸÖ) 3

(פüµÖÖ ÝÖµÖÖ : ²ÖꮕÖÖê‡Ûú ‹×ÃÖ›ü ÛúÖ ´ÖÖê»Ö ¦ü¾µÖ´ÖÖ®Ö = 122 g mol–1, ²ÖꮕÖß®Ö Ûêú ×»ÖµÖê Kf = 4.9 K kg mol–1)

3.9 g of benzoic acid dissolved in 49 g of benzene shows a depression in freezing point

of 1.62 K. Calculate the van’t Hoff factor and predict the nature of solute (associated

or dissociated).

(Given : Molar mass of benzoic acid = 122 g mol–1, Kf for benzene = 4.9 K kg mol–1)

20. (i) Ø•ÖÛú Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûú¸ü®Öê Ûúß ×¾Ö×¬Ö Ûêú ¯Öß”êû •ÖÖê ×ÃÖ¨üÖ®ŸÖ ÆüÖêŸÖÖ Æîü ˆÃÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ …

(ii) ÛúÖò Ö¸ü Ûêú ×®ÖÂÛúÂÖÔÞÖ ´Öë ×ÃÖ×»ÖÛúÖ Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(iii) ¾µÖÖ¯ÖÖ¸üß »ÖÖêÆü ÛúÖ ×¾Ö¿Öã ü ºþ¯Ö »ÖÖêÆü ÛúÖ ÛúÖî®Ö ºþ¯Ö Æîü ? 3

(i) Indicate the principle behind the method used for the refining of zinc.

(ii) What is the role of silica in the extraction of copper ?

(iii) Which form of the iron is the purest form of commercial iron ?

Page 187: Chemistry Past Papers

56/1/2/D 8

21. ´ÖÖê»Ö¸ü ¦ü¾µÖ´ÖÖ®Ö 27 g mol–1 Ûêú ÃÖÖ£Ö ‹Ûú ŸÖŸ¾Ö ÛúÖê ü »Ö´²ÖÖ‡Ô 4.05 × 10–8 cm ¾ÖÖ»Öß ‹Ûú ŒµÖæײÖÛú µÖæ×®Ö™ü

ÃÖê»Ö ²Ö®ÖÖŸÖÖ Æîü … µÖפü ‘Ö®ÖŸ¾Ö 2.7 g cm–3 ÆüÖê, ŸÖÖê ŒµÖæײÖÛú µÖæ×®Ö™ü ÃÖê»Ö ÛúÖ Ã¾Öºþ¯Ö ŒµÖÖ Æîü ? 3

An element with molar mass 27 g mol–1 forms a cubic unit cell with edge length

4.05 × 10–8 cm. If its density is 2.7 g cm–3, what is the nature of the cubic unit cell ?

22. (a) †Ö¯Ö ×®Ö´®Ö ÛúÖê ÛîúÃÖê ÃÖ´Ö—ÖÖ‹ÑÝÖê ?

(i) »Öï£Öî®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö Ûúß †¯ÖêõÖÖ ‹ê׌™ü®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö †×¬ÖÛú Æîü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¸ÓüÝÖß®Ö µÖÖî×ÝÖÛú ²Ö®ÖÖŸÖß Æïü …

(b) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ : 3

2MnO–

4 + 6H+ + 5NO–

2 →

(a) How would you account for the following :

(i) Actinoid contraction is greater than lanthanoid contraction.

(ii) Transition metals form coloured compounds.

(b) Complete the following equation :

2MnO–

4 + 6H+ + 5NO–

2 →

23. ‹Ûú ¯ÖÏ×ÃÖ¨ü ÃÛæú»Ö Ûêú ׯÖÏØÃÖ¯Ö»Ö ÁÖß ¸üÖµÖ ®Öê ‹Ûú ÃÖê×´Ö®ÖÖ¸ü ÛúÖ †ÖµÖÖê•Ö®Ö ×ÛúµÖÖ †Öî ü ˆÃÖ´Öë ˆ®ÆüÖë®Öê ²Ö““ÖÖë Ûêú

†×³Ö³ÖÖ¾ÖÛúÖë ŸÖ£ÖÖ †Öî ü ÃÛæú»ÖÖë Ûêú ׯÖÏØÃÖ¯Ö»ÖÖë ÛúÖê †Ö´ÖÓ×¡ÖŸÖ ×ÛúµÖÖ †Öî ü ÃÖ²Ö®Öê ×´Ö»ÖÛú¸ü ²Ö““ÖÖë ´Öë ´Ö¬Öã ÖêÆü ŸÖ£ÖÖ

ˆ¤üÖÃÖß •ÖîÃÖß ²Öß´ÖÖ׸üµÖÖë Ûêú ²ÖœÌü®Öê Ûêú ÝÖÓ³Ö߸ü ×¾ÖÂÖµÖ ¯Ö¸ü ×¾Ö“ÖÖ¸-ü×¾Ö´Ö¿ÖÔ ×ÛúµÖÖ … ˆ®ÆüÖë®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ×Ûú ÃÛæú»ÖÖë ´Öë

ÃÖ›Ìêü Æãü‹ ÜÖÖª ¯Ö¤üÖ£ÖÔ ¯Ö¸ü ¯ÖÏןֲ֮¬Ö »ÖÝÖÖµÖÖ •ÖÖµÖê †Öî ü þÖÖãµÖ¾Ö¬ÖÔÛú ¯Ö¤üÖ£ÖÔ •ÖîÃÖê ÃÖæ Ö, »ÖÃÃÖß, ¤æü¬Ö †Öפü ˆ¯Ö»Ö²¬Ö

Ûú¸üÖµÖÖ •ÖÖµÖ … ÃÖÖ£Ö Æüß ÃÛæú»ÖÖë ´Öë ¯ÖÏÖŸÖ:ÛúÖ»Öß®Ö ‹ÃÖê ²Ö»Öß Ûêú ÃÖ´ÖµÖ ²Ö““ÖÖë ÛúÖê †Ö¬Öê ‘ÖÓ™êü Ûúß ¿ÖÖ¸üß׸üÛú ÛúÃÖ¸üŸÖ

Ûú¸üÖ‡Ô •ÖÖµÖê … ”û: ´ÖÖÆü Ûêú ¯Ö¿“ÖÖŸÖË ÁÖß ¸üÖµÖ ®Öê ‹Ûú þÖÖãµÖ ×®Ö¸üßõÖÞÖ ¯Öã®Ö: Ûú¸üÖµÖÖ †Öî ü ¤êüÜÖÖ ÝÖµÖÖ ×Ûú ²Ö““ÖÖë Ûêú

þÖÖãµÖ ´Öë †®Öã Ö´Ö ÃÖã¬ÖÖ¸ü Æãü†Ö Æîü …

ˆ¯Ö¸üÖêŒŸÖ ÛúÖê ¯ÖœÌü®Öê Ûêú ²ÖÖ¤ü ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ÁÖß ¸üÖµÖ «üÖ¸üÖ ×Ûú®Ö ´Ö滵ÖÖë (Ûú´Ö ÃÖê Ûú´Ö ¤üÖê) ÛúÖê ¤ü¿ÖÖÔµÖÖ ÝÖµÖÖ Æîü ?

(ii) ‹Ûú ×¾ÖªÖ£Öá Ûêú ºþ¯Ö ´Öë ‡ÃÖ ×¾ÖÂÖµÖ ´Öë †Ö¯Ö ÛîúÃÖê •ÖÖÝÖºþÛúŸÖÖ ±îú»ÖÖµÖëÝÖê ?

(iii) ¿ÖÖ×®ŸÖÛúÖ¸üÛú ŒµÖÖ Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

(iv) ‹Ã¯Öî™ìü´Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ ŒµÖÖë šÓü›êü ³ÖÖê•µÖ ¯Ö¤üÖ£ÖÔ †Öî ü ¯ÖêµÖ ´Öë Æüß ÃÖß×´ÖŸÖ ÆüÖêŸÖÖ Æîü ? 4

Page 188: Chemistry Past Papers

56/1/2/D 9 [P.T.O.

Mr. Roy, the principal of one reputed school organized a seminar in which he invited

parents and principals to discuss the serious issue of diabetes and depression in

students. They all resolved this issue by strictly banning the junk food in schools and

to introduce healthy snacks and drinks like soup, lassi, milk etc. in school canteens.

They also decided to make compulsory half an hour physical activities for the students

in the morning assembly daily. After six months, Mr. Roy conducted the health survey

in most of the schools and discovered a tremendous improvement in the health of

students.

After reading the above passage, answer the following :

(i) What are the values (at least two) displayed by Mr. Roy ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) What are tranquilizers ? Give an example.

(iv) Why is use of aspartame limited to cold foods and drinks ?

24. †ÞÖã ÃÖæ¡Ö C7H7ON ÛúÖ ‹Ûú ‹¸üÖê Öê×™üÛú µÖÖî×ÝÖÛú ‘A’ ®Öß“Öê פüµÖê ÝÖµÖê Ûêú †®ÖãÃÖÖ¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÀÖéÓÜÖ»ÖÖ ¤êüŸÖÖ

Æîü … ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë A, B, C, D †Öî ü E Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ : 5

An aromatic compound ‘A’ of molecular formula C7H7ON undergoes a series of

reactions as shown below. Write the structures of A, B, C, D and E in the following

reactions :

†£Ö¾ÖÖ/OR

Page 189: Chemistry Past Papers

56/1/2/D 10

24. (a) •Ö²Ö ‹×®Ö»Öß®Ö ×®Ö´®Ö †×³ÖÛúÖ¸üÛúÖë Ûêú ÃÖÖ£Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ŸÖ²Ö ´ÖãÜµÖ ˆŸ¯ÖÖ¤üÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) Br2 •Ö»Ö

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) ×®Ö´®Ö ÛúÖê ˆ®ÖÛêú Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ×»Ö×ÜÖ‹ :

C2H5NH2, C2H5OH, (CH3)3N

(c) ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú µÖãÝ´Ö ´Öë ¯ÖÆü“ÖÖ®Ö Ûú¸ü®Öê Ûêú ×»ÖµÖê ‹Ûú ÃÖÖ´ÖÖ®µÖ ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“Ö ¤üßו֋ :

(CH3)2NH †Öî ü (CH3)3N 5

(a) Write the structures of main products when aniline reacts with the following

reagents :

(i) Br2 water

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) Arrange the following in the increasing order of their boiling point :

C2H5NH2, C2H5OH, (CH3)3N

(c) Give a simple chemical test to distinguish between the following pair of

compounds :

(CH3)2NH and (CH3)3N

25. •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë ´Öê×£Ö»Ö ‹êÃÖß™êü™ü Ûêú •Ö»Ö-†¯Ö‘Ö™ü®Ö Ûêú ×»ÖµÖê ×®Ö´®Ö ¯Ö׸üÞÖÖ´Ö ¯ÖÏÖ¯ŸÖ ÆãüµÖê £Öê :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) פüÜÖ»ÖÖ‡‹ ×Ûú µÖÆü ‹Ûú ”û¤Ëü´Ö ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú †®ÖãÃÖÖ¸ü Æîü ŒµÖÖë×Ûú •Ö»Ö ÛúÖ ÃÖÖÓ¦üÞÖ ×ãָü ¸üÆüŸÖÖ

Æîü …

(ii) ÃÖ´ÖµÖ 30 ÃÖê 60 ÃÖêÛúÞ›ü Ûêú ²Öß“Ö †×³Ö×ÛÎúµÖÖ Ûúß †ÖîÃÖŸÖ ¤ü¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(פüµÖÖ ÝÖµÖÖ Æîü log 2 = 0.3010, log 4 = 0.6021) 5

Page 190: Chemistry Past Papers

56/1/2/D 11 [P.T.O.

For the hydrolysis of methyl acetate in aqueous solution, the following results were

obtained :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) Show that it follows pseudo first order reaction, as the concentration of water

remains constant.

(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.

(Given log 2 = 0.3010, log 4 = 0.6021)

†£Ö¾ÖÖ/OR

25. (a) ‹Ûú †×³Ö×ÛÎúµÖÖ A + B → P Ûêú ×»ÖµÖê ¤ü¸ü ¤üß ÝÖ‡Ô Æîü

¤ü¸ü = k[A] [B]2

(i) µÖפü B ÛúÖ ÃÖÖÓ¦üÞÖ ¤üÖê ÝÖã®ÖÖ Ûú¸ü פüµÖÖ •ÖÖµÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß ¤ü¸ü ÛîúÃÖê ¯ÖϳÖÖ×¾ÖŸÖ ÆüÖêÝÖß ?

(ii) µÖפü A ²ÖÆãüŸÖ †×¬ÖÛú ´ÖÖ¡ÖÖ ´Öë ´ÖÖî•Öæ¤ü ÆüÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß Ûãú»Ö ÛúÖê×™ü ŒµÖÖ Æîü ?

(b) ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ 50% ¯Öæ üß ÆüÖê®Öê ´Öë 30 ×´Ö®Ö™ü »ÖêŸÖß Æîü … ‡ÃÖ †×³Ö×ÛÎúµÖÖ ÛúÖê 90% ¯ÖæÞÖÔ ÆüÖê®Öê ´Öë

•ÖÖê ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ˆÃÖÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ …

(log 2 = 0.3010) 5

(a) For a reaction A + B → P, the rate is given by

Rate = k[A] [B]2

(i) How is the rate of reaction affected if the concentration of B is doubled ?

(ii) What is the overall order of reaction if A is present in large excess ?

(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time

required for 90% completion of this reaction.

(log 2 = 0.3010)

26. (a) ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤êüŸÖê Æãü‹ ïÖ™ü Ûúßו֋ :

(i) HF ÃÖê HI Ûúß †Öê ü †´»ÖßµÖ Ã¾Ö³ÖÖ¾Ö ²ÖœÌüŸÖÖ Æîü …

(ii) †ÖòŒÃÖß•Ö®Ö †Öî ü ÃÖ»±ú¸ü Ûêú ×Æü´ÖÖÓÛú †Öî ü Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²Öß“Ö ²Ö›ÌüÖ †ÓŸÖ¸ü Æîü …

(iii) ®ÖÖ‡™ÒüÖê•Ö®Ö ¯Öê®™üÖÆîü»ÖÖ‡›ëü ®ÖÆüà ²Ö®ÖÖŸÖÖ Æîü …

(b) ×®Ö´®Ö Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) Cl F3

(ii) XeF4 5

Page 191: Chemistry Past Papers

56/1/2/D 12

(a) Account for the following :

(i) Acidic character increases from HF to HI.

(ii) There is large difference between the melting and boiling points of oxygen

and sulphur.

(iii) Nitrogen does not form pentahalide.

(b) Draw the structures of the following :

(i) Cl F3

(ii) XeF4

†£Ö¾ÖÖ/OR

26. (i) ±úÖòñúÖê üÃÖ ÛúÖ ÛúÖî®Ö ‹»ÖÖê™ÒüÖò Ö †×¬ÖÛú ÃÖ×ÛÎúµÖ Æîü †Öî ü ŒµÖÖë ?

(ii) ÃÖã Ö¸üÃÖÖê×®ÖÛú •Öê™ü ¯»Öê®Ö †Öê•ÖÖê®Ö ¯ÖŸÖÔ Ûêú †¾ÖõÖµÖ Ûêú ×»Ö‹ ÛîúÃÖê וִ´Öê¤üÖ¸ü Æïü ?

(iii) Cl2 Ûúß †¯ÖêõÖÖ F2 Ûúß †Ö²Ö®¬Ö ×¾ÖµÖÖê•Ö®Ö ‹®£ÖÖß Ûú´Ö ŒµÖÖë Æîü ?

(iv) ´ÖÖîÃÖ´Ö×¾Ö–ÖÖ®Ö ´Öë †¾Ö»ÖÖêÛú®Ö Ûêú ×»ÖµÖê ²Öî»Öæ®ÖÖë ´Öë ³Ö¸ü®Öê Ûêú ×»ÖµÖê ×ÛúÃÖ ˆŸÛéú™ü ÝÖîÃÖ ÛúÖ ¯ÖϵÖÖêÝÖ ×ÛúµÖÖ •ÖÖŸÖÖ

Æîü ?

(v) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯Öæ üÖ Ûúßו֋ :

XeF2 + PF5 → 5

(i) Which allotrope of phosphorus is more reactive and why ?

(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone

layers ?

(iii) F2 has lower bond dissociation enthalpy than Cl2. Why ?

(iv) Which noble gas is used in filling balloons for meteorological observations ?

(v) Complete the equation :

XeF2 + PF5 →

_________

Page 192: Chemistry Past Papers

Qu

es. Value points Marks

1 CH3-CH2-Br

Because it is a primary halide / (10) halide

½ +½

2 BaCl2 because it has greater charge / +2 charge ½ +½

3 X2Y3 1

4 3 1

5 2, 5 - dinitrophenol 1

6. (i)LiAlH4 / NaBH4 /H2, Pt

(ii)KMnO4 , KOH

1

1

7.

7.

When vapour pressure of solution is higher than that predicted by Raoult’s law /

the intermolecular attractive forces between the solute-solvent/(A-B) molecules are weaker than

those between the solute-solute and solvent-solvent molecules/A-A or B-B molecules.

Eg. ethanol-acetone/ethanol-cyclohexane/CS2-acetone or any other correct example

ΔmixH is positive

OR

(a)Azeotropes are binary mixtures having the same composition in the liquid and vapour phase

and boil at a constant temperature.

(b) Minimum boiling azeotrope

eg - ethanol + water or any other example

1

½

½

1

½

½

8. (i)Ag+

(aq) + e- Ag (s)

Reaction with higher E0

value / ∆ G0

negative

(ii) Molar conductivity of a solution at infinite dilution or when concentration approaches

zero

Number of ions per unit volume decreases

½

½

½

½

9. Elements which have partially filled d-orbital in its ground states or any one of its oxidation

states.

1) Variable oxidation states

2) Form coloured ion

Or any other two correct characteristics

1

½ +½

10 1) Diamminedichloridoethylenediaminechromium(III) chloride

2) [Co(NH3)5(ONO)]2+

1+ 1

CHEMISTRY MARKING SCHEME

DELHI -2015

SET -56/1/2/D

Page 193: Chemistry Past Papers

11 (i)

(ii)t2 g3 e g

1

(iii) sp3 , diamagnetic

1

1

½+ ½

12 The cell reaction : Fe(s) + 2H+ (aq) Fe

2+ (aq) + H2(g)

Eocell = E

oc - E

oa

= [0-(-0.44)]V=0.44V

Ecell = Ecell - 0.059 log [ Fe2+

]

2 [ H+]2

Ecell = 0.44 V - 0.059 log ( 0.001 )

2 ( 0.01 ) 2

= 0.44 V - 0.059 log ( 10 )

2

= 0.44 V - 0.0295 V

=≈ 0.410 V

1

1

1

13 (i) mutual coagulation

(ii)strong interaction between dispersed phase and dispersion medium or solvated layer

(iii)CO acts as a poison for catalyst.

1

1

1

14 (i)Hexamethylene diamine NH2 (CH2)6 NH2 and

adipic acid HOOC- (CH2)4- COOH

(ii)3 hydroxybutanoic acid CH3CH(OH)CH2COOH and

3 hydroxypentanoic acid CH3CH2CH(OH)CH2COOH

(iii)Chloroprene H2C=C(Cl)CH=CH2

IUPAC names are accepted

Note : ½ mark for name /s and ½ mark for structure / s

½

½

½

½

½

½

15 (i)CH3CH2CH3

(ii) C6H5COONa + CHI3

(iii)CH4

1

½, ½

1

o

Page 194: Chemistry Past Papers

16.

16.

(i) C6H5OH + NaOH C6H5ONa CH3X C6H5OCH3

Or

C6H5OH + Na C6H5ONa CH3X C6H5OCH3

(ii)CH3CH(OH)CH3 CrO3 or Cu/573K CH3COCH3 (i)CH3MgX (CH3)2C(OH)CH3

(ii)H2O

(iii)C6H5NH2 NaNO2 + HCl C6H5N2Cl H2O warm C6H5OH

273K

OR

a)

b)

(Acetyl chloride instead of acetic anhydride may be used)

1

1

1

½

½

1

1

17 (i)Maltose

(ii) fibrous proteins: parallel polypeptide chain , insoluble in water

Globular proteins: spherical shape, soluble in water, (or any 1 suitable difference)

(iii) Vitamin D

1

1

1

18 (i)Larger surface area, higher van der Waals’ forces , higher the boiling point

(ii)Rotation due to one enantiomer is cancelled by another enantiomer

(iii) - NO2 acts as Electron withdrawing group or –I effect

1

1

1

Page 195: Chemistry Past Papers

19

∆Tf = i Kf m

∆Tf = i Kf mb x1000

Mb x ma

1.62 K = i x 4.9K kg mol-1

x 3.9 g x 1000

122 gmol-1

49 kg

i = 0.506

Or by any other correct method

As i<1 , therefore solute gets associated.

½

1

½

1

20 (i) Zinc being low boiling will distil first leaving behind impurities/ or on electrolysis the pure

metal gets deposited on cathode from anode.

(ii)Silica acts as flux to remove iron oxide which is an impurity as slag or FeO + SiO2 FeSiO3

(iii)Wrought iron

1

1

1

21 d = z x M

a3 NA

z = d a3 NA

M

z = 2.7 g cm-3

x 6.022 x1023

mol-1

x ( 4.05 x 10-8

cm)3

27 g mol-1

= 3.999 ≈ 4

Face centered cubic cell/ fcc

½

1

½

1

22 (i) 5f orbital electrons have poor shielding effect than 4f

(ii)due to d-d transition / or the energy of excitation of an electron from lower d orbital to higher

d-orbital lies in the visible region /presence of unpaired electrons in the d-orbital.

(iii) 2 MnO4- + 6 H

+ + 5 NO2

- 2 Mn

2+ + 3 H2O + 5 NO3

-

1

1

1

23 (i) Concern for students health, Application of knowledge of chemistry to daily life,

empathy , caring or any other

(ii)Through posters, nukkad natak in community, social media, play in assembly or any other

(iii)Tranquilizers are drugs used for treatment of stress or mild and severe mental disorders .. Eg:

equanil (or any other suitable example)

(iv) Aspartame is unstable at cooking temperature.

½, ½

1

½ , ½

1

Page 196: Chemistry Past Papers

24

24.

A = B = C = D = E =

OR

O

a. i)

ii) iii)

b. ( CH3)3N < C2H5NH2 < C2H5OH

c. By Hinsberg test secondary amines ( CH3)2NH shows ppt formation which is

tertiary insoluble in KOH , tertiary amines ( CH3)3N do not react with benzene sulphonyl choride

1x5=

5

1

1

1

1

1

25

(a)

k = 2.303 log [ A0 ]

t [A]

k = 2.303 log 0.60

30 0.30

k = 2.303 x 0.301 = 0.023 s-1

30

k = 2.303 log 0.60

60 0.15

k = 2.303 x 0.6021 = 0.023 s-1

60

1

½

½

1

Page 197: Chemistry Past Papers

25.

As k is constant in both the readings, hence it is a pseudofirst order reaction.

ii)

Rate = - Δ[R]/Δt

= -[0.15-0.30]

60-30

= 0.005 mol L-1

s-1

OR

a) (i) Rate will increase 4 times of the actual rate of reaction.

(ii) Second order reaction

b) t

1/2 = 0.693

k

30min =

0.693

k

k = 0.0231min-1

k = 2.303 log [ A0 ]

t [A]

t = 2.303 log 100

0.0231 10

t = 2.303 min

0.0231

t = 99.7min

½

½

1

1+1

½

½

½

½

1

Page 198: Chemistry Past Papers

26.

26.

(a) (i) Due to decrease in bond dissociation enthalpy from HF to HI , there is an increase in acidic

character observed.

(ii)Oxygen exists as diatomic O2 molecule while sulphur as polyatomic S8

(iii)Due to non availability of d orbitals

(b)

OR

(i) White Phosphorus because it is less stable due to angular strain

(ii)Nitrogen oxides emitted by supersonic jet planes are responsible for depletion of ozone layer.

Or NO+O3 NO2+ O2

(iii)due to small size of F, large inter electronic repulsion / electron- electron repulsion among the

lone pairs of fluorine

(iv)Helium

(v) XeF2 + PF5 [XeF]+ [PF6]

-

1

1

1

1

1

½ , ½

1

1

1

1

Page 199: Chemistry Past Papers

56/2/1/F 1 P.T.O.

narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð >na Adí` bIo§ & Candidates must write the Code on the

title page of the answer-book.

Series SSO/2 H$moS> Z§.

Code No.

amob Z§. Roll No.

agm`Z dkmZ (g¡ÕmpÝVH$)

CHEMISTRY (Theory)

ZYm©[aV g_` : 3 KÊQ>o AYH$V_ A§H$ : 70

Time allowed : 3 hours Maximum Marks : 70

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _o§ _wÐV n¥ð> 15 h¢ &

àíZ-nÌ _| XmhZo hmW H$s Amoa XE JE H$moS >Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na bI| &

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _| >26 àíZ h¢ & H¥$n`m àíZ H$m CÎma bIZm ewê$ H$aZo go nhbo, àíZ H$m H«$_m§H$ Adí` bI| &

Bg àíZ-nÌ H$mo n‹T>Zo Ho$ bE 15 _ZQ >H$m g_` X`m J`m h¡ & àíZ-nÌ H$m dVaU nydm©• _| 10.15 ~Oo H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg AdY Ho$ Xm¡amZ do CÎma-nwpñVH$m na H$moB© CÎma Zht bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

Please check that this question paper contains 26 questions.

Please write down the Serial Number of the question before

attempting it.

15 minute time has been allotted to read this question paper. The question

paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

56/2/1/F

SET-1

Page 200: Chemistry Past Papers

56/2/1/F 2

gm_mÝ` ZXe :

(i) g^r àíZ AZdm`© h¢ &

(ii) àíZ g§»`m 1 go 5 VH$ AV bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 1 A§H$ h¡ &

(iii) àíZ g§»`m 6 go 10 VH$ bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 2 A§H$ h¡§ &

(iv) àíZ g§»`m 11 go 22 VH$ ^r bKw-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 3 A§H$ h¢ &

(v) àíZ g§»`m 23 _yë`mYm[aV àíZ h¡ Am¡a BgHo$ bE 4 A§H$ h¢ &

(vi) àíZ g§»`m 24 go 26 VH$ XrK©-CÎmar` àíZ h¢ Am¡a àË`oH$ àíZ Ho$ bE 5 A§H$ h¢ &

(vii) `X Amdí`H$Vm hmo, Vmo bm°J Q>o~bm| H$m à`moJ H$a| & H¡$ëHw$boQ>am| Ho$ Cn`moJ H$s AZw_V Zht h¡ &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 5 are very short answer questions and carry

1 mark each.

(iii) Questions number 6 to 10 are short answer questions and carry 2 marks

each.

(iv) Questions number 11 to 22 are also short answer questions and carry

3 marks each.

(v) Question number 23 is a value based question and carry 4 marks.

(vi) Questions number 24 to 26 are long answer questions and carry 5 marks

each.

(vii) Use log tables, if necessary. Use of calculators is not allowed.

1. ZåZbIV `w½_ _| H$m¡Z SN2 A^H«$`m AYH$ Vrd«Vm go H$aoJm Am¡a Š`m| ? 1

CH3 CH2 Br Am¡a CH3 CH2 I

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 CH2 Br and CH3 CH2 I

Page 201: Chemistry Past Papers

56/2/1/F 3 P.T.O.

2. gm_mÝ` Vmn_mZ na gë\$a H$m H$m¡Z-gm Anaê$n (EbmoQ´>mon) D$î_r` ê$n go ñWm`r h¡ ? 1

Which allotrope of sulphur is thermally stable at room temperature ?

3. XE JE `m¡JH$ H$m AmB©. y.nr.E.gr. Zm_ bIE : 1

HO CH2 CH = C CH3

CH3

Write the IUPAC name of the given compound :

HO CH2 CH = C CH3

CH3

4. Cg `m¡JH$ H$m gyÌ Š`m h¡ Og_| VÎd Y ccp OmbH$ ~ZmVm h¡ Am¡a X Ho$ na_mUw

AîQ>\$bH$s` [a>º$ H$m 2/3dm± ^mJ KoaVo h¢ ? 1

What is the formula of a compound in which the element Y forms ccp

lattice and atoms of X occupy 2/3rd of octahedral voids ?

5. ^m¡VH$emofU CËH«$_Ur` h¡ O~H$ amgm`ZH$emofU AZwËH«$_Ur` hmoVm h¡ & Š`m| ? 1

Physisorption is reversible while chemisorption is irreversible. Why ?

6. (i) ZåZbIV H$m°åßboŠg H$m AmB©. y.nr.E.gr. Zm_ bIE :

[Cr (en)3]Cl3

(ii) ZåZbIV H$m°åßboŠg H$m gyÌ bIE :

nmoQ>¡e`_ Q´>mB© Am°Šgb¡Q>mo H«$mo_oQ>(III) 2

(i) Write down the IUPAC name of the following complex :

[Cr (en)3]Cl3

(ii) Write the formula for the following complex :

Potassium tri oxalato chromate(III)

Page 202: Chemistry Past Papers

56/2/1/F 4

7. amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ go Š`m VmËn`© h¡ ? EH$ CXmhaU XrOE & G$UmË_H$ dMbZ Ho$ bE ∆mixH H$m Š`m M• hmoVm h¡ ? 2>

AWdm

EµOAmoQ´>mon H$mo n[a^mfV H$sOE & amCëQ> Ho$ Z`_ go G$UmË_H$ dMbZ Ûmam ~ZZo dmbm EµOAmoQ´>mon H$g àH$ma H$m hmoVm h¡ ? EH$ CXmhaU XrOE & 2

What is meant by negative deviation from Raoult’s law ? Give an

example. What is the sign of mixH for negative deviation ?

OR

Define azeotropes. What type of azeotrope is formed by negative

deviation from Raoult’s law ? Give an example.

8. ZåZbIV A^H«$`mAm| _| à`moJ AmZo dmbo A^H$maH$m| Ho$ Zm_ XrOE : 2

(i) CH3 CHO ?

CH3 CH CH3

|

OH

(ii) CH3 COOH ?

CH3 COCl

Name the reagents used in the following reactions :

(i) CH3 CHO ?

CH3 CH CH3 |

OH

(ii) CH3 COOH ?

CH3 COCl

9. (a) Obr` H$m°na(II) ŠbmoamBS> db`Z Ho$ dÚwV ²-AnKQ>Z Ho$ Xm¡amZ H¡$WmoS> na ZåZbIV A^H«$`mE± hmoVr h¢ :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

CZHo$ _mZH$ AnM`Z BboŠQ´>moS> d^d (E0) Ho$ _mZm| Ho$ AmYma na H¡$WmoS> na H$g

A^H«$`m H$s g§^mdZm (gwg§JVVm) h¡ Am¡a Š`m| ?

Page 203: Chemistry Past Papers

56/2/1/F 5 P.T.O.

(b) Am`Zm| Ho$ ñdV§Ì A^J_Z Ho$ H$mobamD$e Z`_ H$m H$WZ H$sOE & BgH$m EH$ AZwà`moJ bIE & 2

(a) Following reactions occur at cathode during the electrolysis of

aqueous copper(II) chloride solution :

Cu2+ (aq) + 2e Cu(s) E0 = + 0·34 V

H+ (aq) + e 2

1 H2(g) E

0 = 0·00 V

On the basis of their standard reduction electrode potential (E0)

values, which reaction is feasible at the cathode and why ?

(b) State Kohlrausch law of independent migration of ions. Write its

one application.

10. g§H«$_U VÎd Š`m| n[adVu CnM`Z AdñWmAm§o H$mo àXe©V H$aVo h¢ ? 3d loUr _| (Sc go Zn)

H$m¡Z-gm VÎd gdm©YH$ CnM`Z AdñWmE± Xem©Vm h¡ Am¡a Š`m| ? 2

Why do transition elements show variable oxidation states ? In 3d series

(Sc to Zn), which element shows the maximum number of oxidation

states and why ?

11. 37·2 g Ob _| NaCl (_mob Ðì`_mZ = 58·5 g mol1) H$s H$VZr _mÌm KwbmB© OmE H$ h_m§H$ 2°C KQ> OmE, `h _mZVo hþE H$ NaCl nyU© ê$n go dKQ>V hmoVm h¡ ?

(Kf Ob Ho$ bE = 1·86 K kg mol1) 3

Calculate the mass of NaCl (molar mass = 58·5 g mol1) to be dissolved in

37·2 g of water to lower the freezing point by 2C, assuming that NaCl

undergoes complete dissociation. (Kf for water = 1·86 K kg mol1)

Page 204: Chemistry Past Papers

56/2/1/F 6

12. ZåZbIV ~hþbH$m| Ho$ EH$bH$m| Ho$ Zm_ Am¡a CZH$s g§aMZmE± bIE : 3

(i) Q>oarbrZ

(ii) ~¡Ho$bmBQ>

(iii) ~wZm-S

Write the names and structures of the monomers of the following

polymers :

(i) Terylene

(ii) Bakelite

(iii) Buna-S

13. (i) ZåZbIV _§o H$m¡Z _moZmog¡Ho$amBS> h¡ : ñQ>mM©, _mëQ>mog, \«$ŠQ>mog, gobwbmog

(ii) Aåbr` Eo_Zmo EogS>m| Am¡a jmar` Eo_Zmo EogS>m| Ho$ ~rM$ Š`m A§Va hmoVm h¡ ?

(iii) Cg dQ>m_Z H$m Zm_ bIE OgH$s H$_r Ho$ H$maU _gy ‹S>m| _| IyZ AmZo bJVm h¡ & 3

(i) Which one of the following is a monosaccharide :

starch, maltose, fructose, cellulose

(ii) What is the difference between acidic amino acids and basic amino

acids ?

(iii) Write the name of the vitamin whose deficiency causes bleeding of

gums.

14. (i) ZH$b Ho$ n[aîH$aU _| H$m_ AmZo dmbr dY Ho$ nrN>o Omo gÕmÝV hmoVm h¡ CgH$m

C„oI H$sOE &

(ii) gmoZo Ho$ ZîH$f©U _| VZw NaCN H$s Š`m ^y_H$m hmoVr h¡ ?

(iii) ‘H$m°na _¡Q>o’ Š`m hmoVm h¡ ? 3

(i) Indicate the principle behind the method used for the refining of

Nickel.

(ii) What is the role of dilute NaCN in the extraction of gold ?

(iii) What is ‘copper matte’ ?

Page 205: Chemistry Past Papers

56/2/1/F 7 P.T.O.

15. 25C na ZåZ gob H$m dÚwV²-dmhH$ ~b (B©.E_.E\$.) n[aH$bV H$sOE : 3

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

Calculate the emf of the following cell at 25C :

Zn | Zn2+ (0.001 M) | | H+ (0.01 M) | H2(g) (1 bar) | Pt(s)

0

)Zn/2Zn(E = 0.76 V, 0

)2

H/H(E = 0.00 V

16. ZåZbIV AdbmoH$Zm| Ho$ bE H$maUm| H$mo XrOE : 3

(i) g_wÐr Ob Am¡a ZXr H$m Ob Ohm± _bVo h¢ dhm± EH$ S>oëQ>m ~Z OmVm h¡ &

(ii) MmaH$mob H$s gVh na N2 J¡g H$s Anojm NH3 J¡g AYH$ erK«Vm go AYemofV hmoVr h¡ &

(iii) MyU© H$E hþE nXmW© AYH$ à^mdembr AYemofH$ hmoVo h¢ &

Give reasons for the following observations :

(i) A delta is formed at the meeting point of sea water and river

water.

(ii) NH3 gas adsorbs more readily than N2 gas on the surface of

charcoal.

(iii) Powdered substances are more effective adsorbents.

17. (i) H$m°åßboŠg [Pt(en)2Cl2]2+ Ho$ Á`m_Vr` g_md`dm| H$mo AmaoIV H$sOE &

(ii) H«$ñQ>b \$sëS> gÕmÝV Ho$ AmYma na `X ∆o > P h¡, Vmo d4 Am`Z H$m BboŠQ´>m°ZH$ dÝ`mg bIE &

(iii) H$m°åßboŠg [Ni(CN)4]2 H$m g§H$aU àH$ma Am¡a Mwå~H$s` ì`dhma bIE & (Ni H$m na_mUw H«$_m§H$ = 28) 3

(i) Draw the geometrical isomers of complex [Pt(en)2Cl2]2+.

(ii) On the basis of crystal field theory, write the electronic

configuration for d4 ion, if o P.

(iii) Write the hybridization type and magnetic behaviour of the

complex [Ni(CN)4]2. (Atomic number of Ni = 28)

Page 206: Chemistry Past Papers

56/2/1/F 8

18. (a) EpëH$b h¡bmBS>| Ob _| KwbZerb Zht h¢ & Š`m| ?

(b) ã`wQ>¡Z-1-Am°b àH$meH$s` ZpîH«$` (Y«wdU AKyU©H$) h¡ naÝVw ã`wQ>¡Z-2-Am°b àH$meH$s` gH«$` (Y«wdU KyU©H$) h¡ & Š`m| ?

(c) `Ún ŠbmoarZ BboŠQ´>m°Z H$mo AmH$f©V H$aZo dmbm J«wn h¡ \$a ^r `h BboŠQ´>m°ZñZohr

Eamo_¡Q>H$ àVñWmnZ A^H«$`mAm| _| Am°Wm- VWm n¡am- ZXeH$ h¡ & Š`m| ? 3

(a) Why are alkyl halides insoluble in water ?

(b) Why is Butan-1-ol optically inactive but Butan-2-ol is optically

active ?

(c) Although chlorine is an electron withdrawing group, yet it is

ortho-, para- directing in electrophilic aromatic substitution

reactions. Why ?

19. ZåZbIV H$m ê$nm§VaU Amn H¡$go H$a|Jo : 3

(i) ~oݵOmoBH$ EgS> H$mo ~oݵO¡pëS>hmBS> _|

(ii) EWmB©Z H$mo EW¡Z¡b _|

(iii) EogrQ>H$ EgS> H$mo _rWoZ _|

AWdm

ZåZbIV A^H«$`mAm| go gå~pÝYV g_rH$aUm| H$mo bIE : 3

(i) ñQ>r\$Z A^H«$`m

(ii) dmoë\$-H$íZa AnM`Z

(iii) EQ>mS>© A^H«$`m How do you convert the following :

(i) Benzoic acid to Benzaldehyde

(ii) Ethyne to Ethanal

(iii) Acetic acid to Methane

OR

Write the equations involved in the following reactions :

(i) Stephen reaction

(ii) Wolff-Kishner reduction

(iii) Etard reaction

Page 207: Chemistry Past Papers

56/2/1/F 9 P.T.O.

20. (a) ZåZbIV H$mo Amn H$maU XoVo hþE H¡$go g_PmE±Jo :

(i) Mn H$m CƒV_ âbwAmoamBS> MnF4 h¡ O~H$ CƒV_ Am°ŠgmBS> Mn2O7

h¡ &

(ii) g§H«$_U YmVwE± Am¡a CZHo$ `m¡JH$ CËàoaH$ JwUY_© Xem©Vo h¢ &

(b) ZåZbIV g_rH$aU H$mo nyU© H$sOE :

3–2

4MnO + 4H+ 3

(a) How would you account for the following :

(i) Highest fluoride of Mn is MnF4 whereas the highest oxide is

Mn2O7.

(ii) Transition metals and their compounds show catalytic

properties.

(b) Complete the following equation :

3–2

4MnO + 4H+

21. ZåZbIV A^H«$`mAm| Ho$ CËnmXm| H$s àmJwº$ H$sOE : 3

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

Predict the products of the following reactions :

(i) CH3 CH = CH2 –

22

62

OH/OH3)ii

HB)i ?

(ii) C6H5 OH )aq(Br2 ?

(iii) CH3CH2OH K573/Cu

?

Page 208: Chemistry Past Papers

56/2/1/F 10

22. EH$ VÎd X (_moba Ðì`_mZ = 60 g mol1) H$m KZËd 6·23 g cm3 h¡ & `X `yZQ> gob Ho$ H$moa H$s bå~mB© 4 × 108 cm h¡, Vmo Š`y~H$ `yZQ> gob Ho$ àH$ma H$s Š`m nhMmZ hmoJr ? 3

An element X (molar mass = 60 g mol1) has a density of 6.23 g cm3.

Identify the type of cubic unit cell, if the edge length of the unit cell is

4 × 108 cm.

23. ~ƒm| _| _Yw_oh Am¡a CXmgr Ho$ ~‹T>Vo Ho$gm| H$mo XoIZo Ho$ ~mX EH$ àgÕ ñHy$b Ho$ qàgnb

lr Mmon ‹S>m Zo EH$ go_Zma H$m Am`moOZ H$`m Og_| CÝhm|Zo ~ƒm| Ho$ A^^mdH$m| VWm AÝ`

ñHy$bm| Ho$ qàgnbm| H$mo Am_§ÌV H$`m & CÝhm|Zo ñHy$bm| _| g ‹S>o hþE ^moÁ` nXmWm] (O§H$ \y$S>) na àV~§Y bJmZo H$m ZU©` b`m, gmW hr `h ZU©` b`m H$ ñHy$bm| _| ñdmñÏ`dY©H$

nXmW© O¡go gyn, bñgr, XÿY AmX H¢$Q>rZm| _| CnbãY H$amB© OmE± & CÝhm|Zo `h ^r ZU©`

b`m H$ àmV:H$mbrZ Egoå~br Ho$ g_` ~ƒm| H$mo àVXZ AmYo K§Q>o H$s emar[aH$ H$gaV ^r H$amB© OmE & N>: _mh níMmV² lr Mmon ‹S>m Zo ~ƒm| Ho$ ñdmñÏ` H$m AYH$V_ dÚmb`m| _|

nwZ: ZarjU H$adm`m Am¡a ~ƒm| Ho$ ñdmñÏ` _| AZwn_ gwYma nm`m J`m &

Cn w©º$ àH$aU H$mo n‹T>Zo Ho$ ~mX, ZåZbIV àíZm| Ho$ CÎma XrOE : 4

(i) lr Mmon ‹S>m Ûmam H$Z _yë`m| (H$_-go-H$_ Xmo) H$mo Xem©`m J`m h¡ ?

(ii) EH$ dÚmWu Ho$ ê$n _|, Amn Bg df` _| H¡$go OmJê$H$Vm \¡$bmE±Jo ?

(iii) AdZ_Z-damoYr S´>J ~Zm S>m°ŠQ>a H$s gbmh Ho$ Š`m| Zht boZ o MmhE ?

(iv) H¥$Ì_ _YwaH$ Ho$ Xmo CXmhaU XrOE &

Seeing the growing cases of diabetes and depression among children,

Mr. Chopra, the principal of one reputed school organized a seminar in

which he invited parents and principals. They all resolved this issue by

strictly banning the junk food in schools and by introducing healthy

snacks and drinks like soup, lassi, milk etc. in school canteens. They also

decided to make compulsory half an hour physical activities for the

students in the morning assembly daily. After six months,

Mr. Chopra conducted the health survey in most of the schools and

discovered a tremendous improvement in the health of students.

Page 209: Chemistry Past Papers

56/2/1/F 11 P.T.O.

After reading the above passage, answer the following questions :

(i) What are the values (at least two) displayed by Mr. Chopra ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) Why should antidepressant drugs not be taken without consulting

a doctor ?

(iv) Give two examples of artificial sweeteners.

24. (a) ZåZbIV nXm| H$mo n[a^mfV H$sOE :

(i) gH«$`U D$Om©

(ii) Xa pñWam§H$

(b) 25% d`moOZ Ho$ bE EH$ àW_ H$moQ> H$s A^H«$`m 10 _ZQ> boVr h¡ & A^H«$`m Ho$ bE t

1/2 H$m n[aH$bZ H$sOE >& 5

(X`m J`m : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

AWdm

(a) EH$ amgm`ZH$ A^H«$`m R P Ho$ bE gm§ÐU _| n[adV©Z ln [R] vs. g_` (s) ZrMo ßbm°Q> _| X`m J`m h¡ :

ln [R]

t (s)

(i) A^H«$`m H$s H$moQ> H$s àmJwº$ H$sOE &

(ii) dH«$ H$m T>bmZ Š`m h¡ ?

(iii) A^H«$`m Ho$ bE Xa pñWam§H$ H$s `yZQ> bIE &

(b) Xem©BE H$ 99% nyU© hmoZo _| Omo g_` bJVm h¡ dh Cg g_` H$m XwJwZm h¡ Omo

A^H«$`m Ho$ 90% nyU© hmoZo _| bJVm h¡ & 5

Page 210: Chemistry Past Papers

56/2/1/F 12

(a) Define the following terms :

(i) Activation energy

(ii) Rate constant

(b) A first order reaction takes 10 minutes for 25% decomposition.

Calculate t1/2

for the reaction.

(Given : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

OR

(a) For a chemical reaction R P, the variation in the concentration,

ln [R] vs. time (s) plot is given as

ln [R]

t (s)

(i) Predict the order of the reaction.

(ii) What is the slope of the curve ?

(iii) Write the unit of rate constant for this reaction.

(b) Show that the time required for 99% completion is double of the

time required for the completion of 90% reaction.

25. (a) ZåZbIV Ho$ H$maU XoVo hþE ñnîQ> H$sOE :

(i)

4NH _| Omo Am~ÝY H$moU h¡ dh NH3 Ho$ H$moU go CƒVa h¡ &

(ii) H2O H$s Anojm H2S H$m ŠdWZm§H$ Ý`yZVa h¡ &

(iii) AnM`Z ì`dhma SO2 go TeO2 H$s Amoa KQ>Vm h¡ &

(b) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) H4P2O7 (nm`amo\$m°ñ\$mo[aH$ EogS>)

(ii) XeF2 5

AWdm

Page 211: Chemistry Past Papers

56/2/1/F 13 P.T.O.

(a) ZåZbIV H$s g§aMZmE± AmaoIV H$sOE :

(i) XeF4

(ii) H2S2O7

(b) ZåZbIV Ho$ H$maU XrOE :

(i) HCl go A^H«$`m go Am`aZ FeCl2 ~ZmVm h¡ Z H$s FeCl3.

(ii) HClO H$s Anojm HClO4 à~bVa Aåb h¡ &

(iii) dJ© 15 Ho$ g^r hmBS´>mBS>m| _| BiH3 à~bV_ AnMm`H$ h¡ & 5

(a) Account for the following :

(i) Bond angle in

4NH is higher than NH3.

(ii) H2S has lower boiling point than H2O.

(iii) Reducing character decreases from SO2 to TeO2.

(b) Draw the structures of the following :

(i) H4P2O7 (Pyrophosphoric acid)

(ii) XeF2

OR

(a) Draw the structures of the following :

(i) XeF4

(ii) H2S2O7

(b) Account for the following :

(i) Iron on reaction with HCl forms FeCl2 and not FeCl3.

(ii) HClO4 is a stronger acid than HClO.

(iii) BiH3 is the strongest reducing agent amongst all the

hydrides of group 15.

Page 212: Chemistry Past Papers

56/2/1/F 14

26. (a) àË`oH$ Ho$ bE Cn wº$ CXmhaU XoVo hþE ZåZbIV A^H«$`mAm| H$mo àXe©V H$sOE :

(i) A_moZrH$aU

(ii) H$pßb¨J (`w½_Z) A^H«$`m

(iii) Eo_rZm| H$m EogrQ>brH$aU

(b) àmW_H$ (àmB_ar), ÛVr`H$ (goH$ÊS>ar) Am¡a V¥Vr`H$ (Q>e©`ar) E_rZm| H$s nhMmZ H$aZo Ho$ bE hÝg~J© dY H$m dU©Z H$sOE & gå~Õ A^H«$`mAm| Ho$ amgm`ZH$ g_rH$aUm| H$mo ^r bIE & 5

AWdm

(a) O~ ~oݵOrZ S>mBEµOmoZ`_ ŠbmoamBS> (C6 H5–

2ClN ) ZåZbIV A^H$maH$m| go

A^H«$`m H$aVm h¡, V~ àmßV _w»` CËnmXm| H$s g§aMZmE± bIE :

(i) HBF4 /

(ii) Cu / HBr

(b) ZåZbIV A^H«$`mAm| _| A, B Am¡a C H$s g§aMZmE± bIE :

5 (a) Illustrate the following reactions giving suitable example in each

case :

(i) Ammonolysis

(ii) Coupling reaction

(iii) Acetylation of amines

(b) Describe Hinsberg method for the identification of primary,

secondary and tertiary amines. Also write the chemical equations

of the reactions involved.

Page 213: Chemistry Past Papers

56/2/1/F 15 P.T.O.

OR

(a) Write the structures of main products when benzene diazonium

chloride (C6 H5–

2ClN ) reacts with the following reagents :

(i) HBF4 /

(ii) Cu / HBr

(b) Write the structures of A, B and C in the following reactions :

Page 214: Chemistry Past Papers

1

Qn Value points Marks

1 CH3CH2I , because I is a better leaving group. ½ , ½

2 Rhombic sulphur 1

3 3-Methylbut-2-en-1-ol 1

4 X2Y3 1

5 Because of weak van der Waals’ forces in physisorption whereas there are strong chemical

forces in chemisorption.

1

6. i) tris-(ethane-1,2-diamine)chromium(III) chloride

ii) K3[ Cr(C2O4)3]

1

1

7.

7.

When solute- solvent interaction is stronger than pure solvent or solute interaction.

Eg: chloroform and acetone (or any other correct eg)

∆mixH= negative

OR

Azeotropes –binary mixtures having same composition in liquid and vapour phase and boil at

constant temperature / is a liquid mixture which distills at constant temperature without

undergoing change in composition

Maximum boiling azeotropes

eg: HNO3 (68%) and H2O(32%) (or any other correct example)

1

½

½

1

½

½

8. (i) CH3MgBr/ H3O+

(ii) PCl5/ PCl3 / SOCl2

1

1

9. a) Cu2+

(aq) + 2 e Cu(s) because of high E0 value/ more negative ∆G

b) It states that limiting molar conductivity of an electrolyte is equal to the sum of the individual

contributions of cations and anions of the electrolyte.

It is used to calculate the Ʌm0 for weak electrolyte / It is used to calculate α and Kc

(Any one application)

½ , ½

1

1

CHEMISTRY MARKING SCHEME 2015

SET -56/2/1 F

Page 215: Chemistry Past Papers

2

10 a) Due to presence of unpaired d-electrons/ comparable energies of 3d and 4s orbitals.

b) Mn , due to involvement of 4s and 3d electrons/ presence of maximum unpaired d-

electrons.

1

½ ,½

11 ∆ Tf = i. Kf m

= i Kf wB x 1000

MB x wA

2K= 2 x 1.86K kg/mol x wB x 1000

58.5 g/mol x 37.2 g

wB = 1.17g

1

1

1

12

i)

ii)

Phenol and formaldehyde

iii)

(Note: half mark for structure/s and half mark for name/s)

1

1

1

13 i) Fructose

ii) Acidic amino acid has more number of acidic carboxylic group than basic amino

group whereas basic amino acid has more number of basic amino group.

iii) Vitamin C

1

1

1

14 a) Impure Ni reacts with CO to form volatile Ni(CO)4 which when heated at higher

temperature decomposes to give pure Ni.

b) NaCN acts as a leaching agent to form a soluble complex with gold.

c) It is a mixture of Cu2S and FeS

1

1

1

Page 216: Chemistry Past Papers

3

15 E cell = E

0 cell –

log

E cell = 0.76 V -

V log

( )

E cell = 0.76 – 0.0295 V log 10

= 0.7305 V

1

1

1

16 i) Due to coagulation of colloidal clay particles.

ii) Because NH3 is easily liquefiable than N2 due to its larger molecular size.

iii) Because of more surface area.

1

1

1

17

i)

cis- isomer trans-isomer

ii) t2g4

iii) dsp 2

, diamagnetic

1

1

1/2 , ½

18 a) Because they are unable to form H-bonds with water molecules.

b) Because of the presence of chiral carbon in butan-2-ol.

c) Due to dominating +R effect

1

1

1

19

19.

i) C6H5COOH PCl5 C6H5COCl H2/Pd C6H5CHO

BaSO4

ii) CH≡CH + H2O Hg2+

/H2SO4 CH3CHO

iii) CH3COOH NaOH

CH3COONa NaOH + CaO , heat

CH4

OR

i)

ii)

iii)

1

1

1

1

1

1

Page 217: Chemistry Past Papers

4

20 i) Because oxygen stabilizes Mn more than F due to multiple bonding

ii) Because of their ability to show variable oxidation state(or any other correct reason)

iii) 3MnO42-

+ 4H+ 2MnO4

- + MnO2 + 2H2O

1

1

1

21 i) CH3CH2CH2OH

ii)

iii) CH3CHO

1

1

1

22 d=

6.23 g cm-3

=

( )

z=4

fcc

½

½

1

1

23 a) Concern for students health, Application of knowledge of chemistry to daily life, empathy

, caring or any other

b) Through posters, nukkad natak in community, social media, play in assembly (or any other

relevant answer)

c) Wrong choice and overdose may be harmful

d) Aspartame, saccharin (or any other correct example)

½ , ½

1

1

½+ ½

24

a)i) Activation energy- Extra energy required by reactants to form activated complex.

ii) Rate constant- rate of reaction when the concentration of reactant is unity.

b)

k= 2.303 log [ A0 ]

t [A]

k = 2.303 log 100

10 min 75

k = 2.303 x 0.125

10 min

1

1

½

½

Page 218: Chemistry Past Papers

5

24.

k = 0.02879 min-1

t1/2 =

=

t1/2 = 24.07min

OR

a) i)First order ii) -k iii) s-1

b)

t =

log

t99% =

log

t =

x 2

t90% =

log

=

t99% = 2 x t90%

1

1

1,1,1

½

½

1

25

a) i)Because of lone pair in NH3 , lone pair- bond pair repulsion decreases the bond angle

ii)Because of absence of H-bonding in H2S

iii)Because stability of +4 oxidation state increases from SO2 to TeO2

b)

OR

1

1

1

1,1

Page 219: Chemistry Past Papers

6

25.

a)

b)i)Because iron on reaction with HCl produces H2(g) which prevents the formation of FeCl2 to

FeCl3 / Because HCl is a weak oxidising agent.

ii) Because of higher oxidation state of chlorine in HClO4

iii) Because of lower dissociation enthalpy of Bi-H bond.

1,1

1

1

1

26

a) i)ammonolysis

ii)

(any one)

iii) (or any other correct reaction)

1

1

1

Page 220: Chemistry Past Papers

7

Sr. Name Sr. Name

26.

b)reaction of primary amine

(soluble in alkali)

Reaction of secondary amine

(insoluble in alkali)

Tertiary amine doesn’t react

OR

a) i)

ii)

b) i) A- B- C-

ii) A- CH3CN B- CH3CH2NH2 C- CH3CH2OH

1

1

1

1

½,½,

½

½ ,½,

½

Page 221: Chemistry Past Papers

8

No. No.

Page 222: Chemistry Past Papers

56/1/2/D 1 [P.T.O.

¸üÖê»Ö ®ÖÓ.

Roll No.

¸üÃÖÖµÖ®Ö ×¾Ö–ÖÖ®Ö (ÃÖî üÖ×®ŸÖÛú) CHEMISTRY (Theory)

×®Ö¬ÖÖÔ׸üŸÖ ÃÖ´ÖµÖ : 3 ‘ÖÞ™êüü] [†×¬ÖÛúŸÖ´Ö †ÓÛúú : 70

Time allowed : 3 hours ] [ Maximum Marks : 70

ÃÖÖ´ÖÖ®µÖ ×®Ö¤ìü¿Ö :

(i) ÃÖ³Öß ¯ÖÏ¿®Ö †×®Ö¾ÖÖµÖÔ Æïü …

(ii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 1 ÃÖê 5 ŸÖÛú †×ŸÖ »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 1 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æîü …

(iii) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 6 ÃÖê 10 ŸÖÛú »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 2 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(iv) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 11 ÃÖê 22 ŸÖÛú ³Öß »Ö‘Öã-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 3 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(v) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 23 ´Ö滵ÖÖ¬ÖÖ׸üŸÖ ¯ÖÏ¿®Ö Æîü †Öî ü ‡ÃÖÛêú ×»Ö‹ 4 †ÓÛú ×®Ö¬ÖÖÔ׸üŸÖ Æïü …

(vi) ¯ÖÏ¿®Ö-ÃÖÓܵÖÖ 24 ÃÖê 26 ¤üß‘ÖÔ-ˆ¢Ö¸üßµÖ ¯ÖÏ¿®Ö Æïü … ¯ÖÏŸµÖêÛú ¯ÖÏ¿®Ö Ûêú ×»Ö‹ 5 †ÓÛú Æïü …

(vii) µÖפü †Ö¾Ö¿µÖÛú ÆüÖê ŸÖÖê »ÖÖòÝÖ ™êü²Ö»Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ Ûú¸ü ÃÖÛúŸÖê Æïü … Ûîú»ÖÛãú»Öê™ü¸ü Ûêú ˆ¯ÖµÖÖêÝÖ Ûúß †®Öã Ö×ŸÖ ®ÖÆüà Æîü …

Series : SSO/1 ÛúÖê›ü ®ÖÓ. Code No.

56/1/2/D

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ´ÖãצüŸÖ ¯Öéšü 12 Æïü …

• ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë ¤üÖ×Æü®Öê ÆüÖ£Ö Ûúß †Öê ü פü‹ ÝÖ‹ ÛúÖê›ü ®Ö´²Ö¸ü ÛúÖê ”ûÖ¡Ö ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü ×»ÖÜÖë …

• Ûéú¯ÖµÖÖ •ÖÖÑ“Ö Ûú¸ü »Öë ×Ûú ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ´Öë 26 ¯ÖÏ¿®Ö Æïü …

• Ûéú¯ÖµÖÖ ¯ÖÏ¿®Ö ÛúÖ ˆ¢Ö¸ü ×»ÖÜÖ®ÖÖ ¿Öãºþ Ûú¸ü®Öê ÃÖê ¯ÖÆü»Öê, ¯ÖÏ¿®Ö ÛúÖ ÛÎú´ÖÖÓÛú †¾Ö¿µÖ ×»ÖÜÖë …

• ‡ÃÖ ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖê ¯ÖœÌü®Öê Ûêú ×»Ö‹ 15 ×´Ö®Ö™ü ÛúÖ ÃÖ´ÖµÖ ×¤üµÖÖ ÝÖµÖÖ Æîü … ¯ÖÏ¿®Ö-¯Ö¡Ö ÛúÖ ×¾ÖŸÖ¸üÞÖ ¯Öæ¾ÖÖÔÆËü®Ö ´Öë 10.15 ²Ö•Öê ×ÛúµÖÖ •ÖÖµÖêÝÖÖ … 10.15 ²Ö•Öê ÃÖê 10.30 ²Ö•Öê ŸÖÛú ”ûÖ¡Ö Ûêú¾Ö»Ö ¯ÖÏ¿®Ö-¯Ö¡Ö ¯ÖœÌëüÝÖê †Öî ü ‡ÃÖ †¾Ö×¬Ö Ûêú ¤üÖî üÖ®Ö ¾Öê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ ¯Ö¸ü ÛúÖê‡Ô ˆ¢Ö¸ü ®ÖÆüà ×»ÖÜÖëÝÖê …

• Please check that this question paper contains 12 printed pages.

• Code number given on the right hand side of the question paper should be written on the

title page of the answer-book by the candidate.

• Please check that this question paper contains 26 questions.

• Please write down the Serial Number of the question before attempting it.

• 15 minutes time has been allotted to read this question paper. The question paper will be

distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will only read the

question paper and will not write any answer on the answer-book during this period.

¯Ö¸üßõÖÖ£Öá ÛúÖê›ü ÛúÖê ˆ¢Ö¸ü-¯Öã×ßÖÛúÖ Ûêú ´ÖãÜÖ-¯Öéšü ¯Ö¸ü †¾Ö¿µÖ ×»ÖÜÖë … Candidates must write the Code on

the title page of the answer-book.

SET – 2

Page 223: Chemistry Past Papers

56/1/2/D 2

General Instructions :

(i) All questions are compulsory.

(ii) Q. no. 1 to 5 are very short answer questions and carry 1 mark each.

(iii) Q. no. 6 to 10 are short answer questions and carry 2 marks each.

(iv) Q. no. 11 to 22 are also short answer questions and carry 3 marks each.

(v) Q. no. 23 is a value based question and carry 4 marks.

(vi) Q. no. 24 to 26 are long answer questions and carry 5 marks each.

(vii) Use log tables if necessary, use of calculators is not allowed.

1. ×®Ö´®Ö µÖãÝ´Ö ´Öë ÛúÖî®Ö SN2 †×³Ö×ÛÎúµÖÖ †×¬ÖÛú ŸÖß¾ÖΟÖÖ ÃÖê Ûú êüÝÖÖ †Öî ü ŒµÖÖë ? 1

CH3 – CH2 – Br ŸÖ£ÖÖ CH3 –

C|

C|

B

H3

r

CH3

Which would undergo SN2 reaction faster in the following pair and why ?

CH3 – CH2 – Br and CH3 –

C|

C|

B

H3

r

CH3

2. BaCl2 †Öî ü KCl ´Öë ÃÖê ÛúÖî®Ö ŠúÞÖÖŸ´ÖÛú “ÖÖ•ÖÔ ¾ÖÖ»Öê ÛúÖê»ÖÖ‡›üß ÃÖÖò»Ö ÛúÖ ÃÛÓú¤ü®Ö †×¬ÖÛú ¯ÖϳÖÖ¾Ö¿ÖÖ»Öß œÓüÝÖ ÃÖê

Ûú¸êüÝÖÖ ? ÛúÖ¸üÞÖ ¤üßו֋ … 1

Out of BaCl2 and KCl, which one is more effective in causing coagulation of a

negatively charged colloidal Sol ? Give reason.

3. ˆÃÖ µÖÖî×ÝÖÛú ÛúÖ ÃÖæ¡Ö ŒµÖÖ ÆüÖêÝÖÖ ×•ÖÃÖ´Öë Y ŸÖ¢¾Ö ccp •ÖÖ»ÖÛú ²Ö®ÖÖŸÖÖ Æîü †Öî ü X “ÖŸÖã±ú»ÖÛúßµÖ ×¸ü׌ŸÖ ÛúÖ 1/3¾ÖÖÑ

³ÖÖÝÖ ‘Öê üŸÖÖ Æîü ? 1

What is the formula of a compound in which the element Y forms ccp lattice and

atoms of X occupy 1/3rd

of tetrahedral voids ?

Page 224: Chemistry Past Papers

56/1/2/D 3 [P.T.O.

4. H3PO4 Ûúß õÖÖ¸üÛúŸÖÖ ŒµÖÖ Æîü ? 1

What is the basicity of H3PO4 ?

5. פüµÖê ÝÖµÖê µÖÖî×ÝÖÛú ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö ×»Ö×ÜÖ‹ : 1

Write the IUPAC name of the given compound :

6. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë ¯ÖϵÖãŒŸÖ †×³ÖÛúÖ¸üÛúÖë Ûêú ®ÖÖ´Ö ¤üßו֋ : 2

Name the reagents used in the following reactions :

(i) CH3 – CO – CH3 ?

→ CH3 – C|

O

H

H

– CH3

(ii) C6H5 – CH2 – CH3

?→ C6H5 – COO–K+

7. ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ŒµÖÖ ŸÖÖŸ¯ÖµÖÔ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö Ûêú ×»ÖµÖê

∆mixH ÛúÖ ×“ÖÅ®Öü ŒµÖÖ Æîü ? 2

What is meant by positive deviations from Raoult’s law ? Give an example. What is

the sign of ∆mixH for positive deviation ?

†£Ö¾ÖÖ/OR

7. ‹×•ÖµÖÖê™ÒüÖê ÃÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ¸üÖˆ»™ü ×®ÖµÖ´Ö ÃÖê ¬Ö®ÖÖŸ´ÖÛú ×¾Ö“Ö»Ö®Ö ÃÖê ¯ÖÏÖ¯ŸÖ ‹×•ÖµÖÖê™ÒüÖê Ö ×ÛúÃÖ ¯ÖÏÛúÖ¸ü ÛúÖ

ÆüÖêŸÖÖ Æîü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ … 2

Define azeotropes. What type of azeotrope is formed by positive deviation from

Raoult’s law ? Give an example.

Page 225: Chemistry Past Papers

56/1/2/D 4

8. (a) ×ÃÖ»¾Ö¸ü Œ»ÖÖê üÖ‡›ü Ûêú •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö Ûêú ×¾ÖªãŸÖ †¯Ö‘Ö™ü®Ö ´Öë Ûîú£ÖÖê›ü ¯Ö¸ü ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ‹Ñ ÆüÖêŸÖß Æïü :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

ˆ®ÖÛêú ´ÖÖ®ÖÛú †¯Ö“ÖµÖ®Ö ‡»ÖꌙÒüÖê›ü ×¾Ö³Ö¾Ö (E°) Ûêú ´ÖÖ®ÖÖë Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü Ûîú£ÖÖê›ü ¯Ö¸ü ×ÛúÃÖ †×³Ö×ÛÎúµÖÖ Ûúß

ÃÖÓ³ÖÖ¾Ö®ÖÖ Æîü †Öî ü ŒµÖÖë ?

(b) ÃÖß´ÖÖÓŸÖ ´ÖÖê»Ö¸ü “ÖÖ»ÖÛúŸÖÖ ÛúÖê ¯Ö׸ü³ÖÖ×ÂÖŸÖ Ûúßו֋ … ×¾ÖªãŸÖË †¯Ö‘Ö™ËüµÖ Ûúß “ÖÖ»ÖÛúŸÖÖ ÃÖÖÓ¦üÞÖ Ûêú ‘Ö™ü®Öê Ûêú ÃÖÖ£Ö

ŒµÖÖë Ûú´Ö ÆüÖê®Öê »ÖÝÖŸÖß Æîü ? 2

(a) Following reactions occur at cathode during the electrolysis of aqueous silver

chloride solution :

Ag+(aq) + e– → Ag(s) E° = +0.80 V

H+(aq) + e– → 1

2H2(g) E° = 0.00 V

On the basis of their standard reduction electrode potential (E°) values, which

reaction is feasible at the cathode and why ?

(b) Define limiting molar conductivity. Why conductivity of an electrolyte solution

decreases with the decrease in concentration ?

9. ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾Ö ŒµÖÖ Æïü ? ÃÖÓÛÎú´ÖÞÖ ŸÖŸ¾ÖÖë Ûúß ¤üÖê ×¾Ö¿ÖêÂÖŸÖÖ†Öë ÛúÖê ×»Ö×ÜÖ‹ … 2

What are the transition elements ? Write two characteristics of the transition elements.

10. (i) ÛúÖò ¯»ÖêŒÃÖ [Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine) ÛúÖ †Ö‡Ô.µÖæ.¯Öß.‹.ÃÖß. ®ÖÖ´Ö

×»Ö×ÜÖµÖê …

(ii) ×®Ö´®Ö ÛúÖò ¯»ÖêŒÃÖ ÛúÖ ÃÖæ¡Ö ×»Ö×ÜÖ‹ :

¯Öê®™üÖ‹ê ÖÖ‡®Ö®ÖÖ‡™ÒüÖ‡™üÖê-o-ÛúÖê²ÖÖ»™ü (III). 2

(i) Write down the IUPAC name of the following complex :

[Cr(NH3)2Cl2(en)]Cl (en = ethylenediamine)

(ii) Write the formula for the following complex :

Pentaamminenitrito-o-Cobalt (III).

Page 226: Chemistry Past Papers

56/1/2/D 5 [P.T.O.

11. (i) ÛúÖò ¯»ÖêŒÃÖ [Pt(NH3)2Cl2] Ûêú •µÖÖ×´ÖŸÖßµÖ ÃÖ´ÖÖ¾ÖµÖ¾Ö ÛúÖê †Ö êü×ÜÖŸÖ Ûúßו֋ …

(ii) ×ÛÎúÙü»Ö ±úß»›ü ×ÃÖ¨üÖ®ŸÖ Ûêú †Ö¬ÖÖ¸ü ¯Ö¸ü µÖפü ∆o < P ÆüÖê ŸÖÖê d4 ÛúÖ ‡»ÖꌙÒüÖò®Ö ×¾Ö®µÖÖÃÖ ×»Ö×ÜÖ‹ …

(iii) ÛúÖò ¯»ÖêŒÃÖ [Ni(CO)4] ÛúÖ ÃÖÓÛú¸üÞÖ †Öî ü “Öã ²ÖÛúßµÖ ¯ÖÏÛéú×ŸÖ ×»Ö×ÜÖ‹ … (¯Ö.ÃÖÓ. Ni = 28) 3

(i) Draw the geometrical isomers of complex [Pt(NH3)2Cl2].

(ii) On the basis of crystal field theory, write the electronic configuration for d4 ion

if ∆o < P.

(iii) Write the hybridization and magnetic behaviour of the complex [Ni(CO)4].

(At.no. of Ni = 28)

12. ×®Ö´®Ö ÃÖê»Ö Ûúß 25 °C ¯Ö¸ü emf ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V 3

Calculate emf of the following cell at 25 °C :

Fe | Fe2+(0.001 M) || H+(0.01 M) | H2(g) (1 bar) | Pt(s)

E°(Fe2+ | Fe) = –0.44 V E°(H+ | H2) = 0.00 V

13. ×®Ö´®Ö †¾Ö»ÖÖêÛú®ÖÖë Ûêú ×»ÖµÖê ÛúÖ¸üÞÖ ¤üßו֋ :

(i) “Ö´ÖÔ¿ÖÖê¬Ö®Ö Ûêú ²ÖÖ¤ü “Ö´Ö›ÌüÖ ÃÖÜŸÖ ÆüÖê •ÖÖŸÖÖ Æîü …

(ii) ¦ü¾Ö ×¾Ö¸üÖê¬Öß ÃÖÖò»Ö Ûúß †¯ÖêõÖÖ ¦ü¾ÖîÖêÆüß ÃÖÖò»Ö †×¬ÖÛú ãÖÖµÖß ÆüÖêŸÖÖ Æîü …

(iii) •Ö²Ö Æîü²Ö¸ü ¯ÖÏÛÎú´Ö «üÖ¸üÖ †´ÖÖê×®ÖµÖÖ ²Ö®ÖÖµÖÖ •ÖÖŸÖÖ Æîü ŸÖ²Ö CO ÛúÖê ¤æü¸ü ¸üÜÖ®ÖÖ †Ö¾Ö¿µÖÛú ÆüÖêŸÖÖ Æîü … 3

Give reasons for the following observations :

(i) Leather gets hardened after tanning.

(ii) Lyophilic sol is more stable than lyophobic sol.

(iii) It is necessary to remove CO when ammonia is prepared by Haber’s process.

14. ×®Ö´®Ö ²ÖÆãü»ÖÛúÖë Ûêú ‹Ûú»ÖÛúÖë Ûêú ®ÖÖ´Ö ¾Ö ˆ®ÖÛúß ÃÖÓ ü“Ö®ÖÖµÖë ×»Ö×ÜÖ‹ :

(i) ®ÖÖµÖ»ÖÖò®Ö-6, 6

(ii) PHBV

(iii) ®Ö߆Öê ÖÏß®Ö 3

Write the names and structures of the monomers of the following polymers :

(i) Nylon-6, 6

(ii) PHBV

(iii) Neoprene

Page 227: Chemistry Past Papers

56/1/2/D 6

15. ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ˆŸ¯ÖÖ¤üÖë Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

? 3

Predict the products of the following reactions :

(i) CH3 – C|C

=

H3

O (i) H2N – NH3

→(ii) KOH/Glycol, ∆

?

(ii) C6H5 – CO – CH3 NaOH/I2

→ ? + ?

(iii) CH3 COONa NaOH / CaO

→∆

?

16. ×®Ö´®Ö ºþ¯ÖÖÓŸÖ¸üÞÖ †Ö¯Ö ÛîúÃÖê Ûú¸ëüÝÖê ?

(i) ±úß®ÖÖò»Ö ÛúÖê ‹ê×®ÖÃÖÖò»Ö ´Öë

(ii) ¯ÖÏÖê Öî®Ö-2-†Öò»Ö ÛúÖê 2-´Öê×£Ö»Ö¯ÖÏÖê Öî®Ö-2-†Öò»Ö ´Öë

(iii) ‹ê×®Ö»Öß®Ö ÛúÖê ±úß®ÖÖò»Ö ´Öë 3

How do you convert the following :

(i) Phenol to anisole

(ii) Propan-2-ol to 2-methylpropan-2-ol

(iii) Aniline to phenol

†£Ö¾ÖÖ/OR

16. (a) ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ Ûúß ×ÛÎúµÖÖ-×¾Ö×¬Ö ÛúÖê ×»Ö×ÜÖ‹ :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) ÃÖî×»Ö×ÃÖ×»ÖÛú ‹ê×ÃÖ›ü Ûêú ‹êÃÖß™üß»ÖßÛú¸üÞÖ ÃÖê ÃÖ´²Ö¨ü ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ×»Ö×ÜÖ‹ … 3

(a) Write the mechanism of the following reaction :

2CH3CH2OH H+

→ CH3CH2 – O – CH2CH3

(b) Write the equation involved in the acetylation of Salicylic acid.

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56/1/2/D 7 [P.T.O.

17. (i) ×®Ö´®Ö ´Öë ÃÖê ÛúÖî®Ö ›üÖ‡ÔÃÖîÛêú¸üÖ‡›ü Æîü : ÙüÖ“ÖÔ, ´ÖÖ»™üÖêÃÖ, ±ÏúŒ™üÖêÃÖ, Ý»ÖæÛúÖêÃÖ ?

(ii) ¸êü¿Öê¤üÖ¸ü ¯ÖÏÖê™üß®Ö †Öî ü ÝÖÖê»ÖÖÛúÖ¸ü ¯ÖÏÖê™üß®Ö ´Öë ŒµÖÖ †ÓŸÖ¸ü Æîü ?

(iii) ²Ö““ÖÖë ´Öë ×ÛúÃÖ ×¾Ö™üÖ×´Ö®Ö Ûúß Ûú´Öß Ûêú ÛúÖ¸üÞÖ Æüøüß ´Öë Ûãúºþ¯ÖŸÖÖ ÆüÖê •ÖÖŸÖß Æîü ? 3

(i) Which one of the following is a disaccharide : Starch, Maltose, Fructose,

Glucose ?

(ii) What is the difference between fibrous protein and globular protein ?

(iii) Write the name of vitamin whose deficiency causes bone deformities in children.

18. ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤üßו֋ :

(a) t-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›üü Ûúß †¯ÖêõÖÖ n-²µÖæ×™ü»Ö ²ÖÎÖê ÖÖ‡›ü ÛúÖ Œ¾Ö£Ö®ÖÖÓÛú ˆ““ÖŸÖ¸ü ÆüÖêŸÖÖ Æîü …

(b) ¸îüÃÖê×´ÖÛú ×´ÖÁÖÞÖ ¯ÖÏÛúÖ¿ÖÛúßµÖ ×®Ö×ÂÛÎúµÖ Æïü …

(c) ®ÖÖ׳ÖÛúîÖêÆüß ¯ÖÏןÖãÖÖ¯Ö®Ö †×³Ö×ÛÎúµÖÖ†Öë Ûêú ¯ÖÏ×ŸÖ Æîü»ÖÖꋸüß®ÖËÃÖ Ûúß ÃÖ×ÛÎúµÖŸÖÖ ²ÖœÌü •ÖÖŸÖß Æîü µÖפü o/p ¯ÖÖê•Öß¿Ö®Ö ¯Ö¸ü ®ÖÖ‡™ÒüÖê ÝÖÏã Ö (–NO2) ˆ¯Ö×Ã£ÖŸÖ ÆüÖê … 3

Give reasons :

(a) n-Butyl bromide has higher boiling point than t-butyl bromide.

(b) Racemic mixture is optically inactive.

(c) The presence of nitro group (–NO2) at o/p positions increases the reactivity of

haloarenes towards nucleophilic substitution reactions.

19. ²ÖꮕÖß®Ö Ûêú 49 g ´Öë ²ÖꮕÖÖê‡Ûú †´»Ö ÛúÖ 3.9 g ‘Öã»Ö®Öê ¯Ö¸ü ×Æü´ÖÖÓÛú ´Öë 1.62 K ÛúÖ †¾Ö®Ö´Ö®Ö ÆüÖê •ÖÖŸÖÖ Æîü … ¾Öî®™ü ÆüÖ±ú ÛúÖ¸üÛú ÛúÖê ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ †Öî ü ×¾Ö»ÖêµÖ Ûêú þֳÖÖ¾Ö Ûúß ¯ÖÏÖÝÖã׌ŸÖ Ûúßו֋ (ÃÖÓÝÖã×ÞÖŸÖ µÖÖ ×¾Ö‘Ö×™üŸÖ) 3

(פüµÖÖ ÝÖµÖÖ : ²ÖꮕÖÖê‡Ûú ‹×ÃÖ›ü ÛúÖ ´ÖÖê»Ö ¦ü¾µÖ´ÖÖ®Ö = 122 g mol–1, ²ÖꮕÖß®Ö Ûêú ×»ÖµÖê Kf = 4.9 K kg mol–1)

3.9 g of benzoic acid dissolved in 49 g of benzene shows a depression in freezing point

of 1.62 K. Calculate the van’t Hoff factor and predict the nature of solute (associated

or dissociated).

(Given : Molar mass of benzoic acid = 122 g mol–1, Kf for benzene = 4.9 K kg mol–1)

20. (i) Ø•ÖÛú Ûêú ¯Ö׸üÂÛú¸üÞÖ Ûú¸ü®Öê Ûúß ×¾Ö×¬Ö Ûêú ¯Öß”êû •ÖÖê ×ÃÖ¨üÖ®ŸÖ ÆüÖêŸÖÖ Æîü ˆÃÖÛúÖ ÃÖÓÛêúŸÖ Ûúßו֋ …

(ii) ÛúÖò Ö¸ü Ûêú ×®ÖÂÛúÂÖÔÞÖ ´Öë ×ÃÖ×»ÖÛúÖ Ûúß ŒµÖÖ ³Öæ×´ÖÛúÖ ÆüÖêŸÖß Æîü ?

(iii) ¾µÖÖ¯ÖÖ¸üß »ÖÖêÆü ÛúÖ ×¾Ö¿Öã ü ºþ¯Ö »ÖÖêÆü ÛúÖ ÛúÖî®Ö ºþ¯Ö Æîü ? 3

(i) Indicate the principle behind the method used for the refining of zinc.

(ii) What is the role of silica in the extraction of copper ?

(iii) Which form of the iron is the purest form of commercial iron ?

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56/1/2/D 8

21. ´ÖÖê»Ö¸ü ¦ü¾µÖ´ÖÖ®Ö 27 g mol–1 Ûêú ÃÖÖ£Ö ‹Ûú ŸÖŸ¾Ö ÛúÖê ü »Ö´²ÖÖ‡Ô 4.05 × 10–8 cm ¾ÖÖ»Öß ‹Ûú ŒµÖæײÖÛú µÖæ×®Ö™ü

ÃÖê»Ö ²Ö®ÖÖŸÖÖ Æîü … µÖפü ‘Ö®ÖŸ¾Ö 2.7 g cm–3 ÆüÖê, ŸÖÖê ŒµÖæײÖÛú µÖæ×®Ö™ü ÃÖê»Ö ÛúÖ Ã¾Öºþ¯Ö ŒµÖÖ Æîü ? 3

An element with molar mass 27 g mol–1 forms a cubic unit cell with edge length

4.05 × 10–8 cm. If its density is 2.7 g cm–3, what is the nature of the cubic unit cell ?

22. (a) †Ö¯Ö ×®Ö´®Ö ÛúÖê ÛîúÃÖê ÃÖ´Ö—ÖÖ‹ÑÝÖê ?

(i) »Öï£Öî®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö Ûúß †¯ÖêõÖÖ ‹ê׌™ü®ÖÖêµÖ›ü ÃÖÓÛãú“Ö®Ö †×¬ÖÛú Æîü …

(ii) ÃÖÓÛÎú´ÖÞÖ ¬ÖÖŸÖã‹Ñ ¸ÓüÝÖß®Ö µÖÖî×ÝÖÛú ²Ö®ÖÖŸÖß Æïü …

(b) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯ÖæÞÖÔ Ûúßו֋ : 3

2MnO–

4 + 6H+ + 5NO–

2 →

(a) How would you account for the following :

(i) Actinoid contraction is greater than lanthanoid contraction.

(ii) Transition metals form coloured compounds.

(b) Complete the following equation :

2MnO–

4 + 6H+ + 5NO–

2 →

23. ‹Ûú ¯ÖÏ×ÃÖ¨ü ÃÛæú»Ö Ûêú ׯÖÏØÃÖ¯Ö»Ö ÁÖß ¸üÖµÖ ®Öê ‹Ûú ÃÖê×´Ö®ÖÖ¸ü ÛúÖ †ÖµÖÖê•Ö®Ö ×ÛúµÖÖ †Öî ü ˆÃÖ´Öë ˆ®ÆüÖë®Öê ²Ö““ÖÖë Ûêú

†×³Ö³ÖÖ¾ÖÛúÖë ŸÖ£ÖÖ †Öî ü ÃÛæú»ÖÖë Ûêú ׯÖÏØÃÖ¯Ö»ÖÖë ÛúÖê †Ö´ÖÓ×¡ÖŸÖ ×ÛúµÖÖ †Öî ü ÃÖ²Ö®Öê ×´Ö»ÖÛú¸ü ²Ö““ÖÖë ´Öë ´Ö¬Öã ÖêÆü ŸÖ£ÖÖ

ˆ¤üÖÃÖß •ÖîÃÖß ²Öß´ÖÖ׸üµÖÖë Ûêú ²ÖœÌü®Öê Ûêú ÝÖÓ³Ö߸ü ×¾ÖÂÖµÖ ¯Ö¸ü ×¾Ö“ÖÖ¸-ü×¾Ö´Ö¿ÖÔ ×ÛúµÖÖ … ˆ®ÆüÖë®Öê ×®ÖÞÖÔµÖ ×ÛúµÖÖ ×Ûú ÃÛæú»ÖÖë ´Öë

ÃÖ›Ìêü Æãü‹ ÜÖÖª ¯Ö¤üÖ£ÖÔ ¯Ö¸ü ¯ÖÏןֲ֮¬Ö »ÖÝÖÖµÖÖ •ÖÖµÖê †Öî ü þÖÖãµÖ¾Ö¬ÖÔÛú ¯Ö¤üÖ£ÖÔ •ÖîÃÖê ÃÖæ Ö, »ÖÃÃÖß, ¤æü¬Ö †Öפü ˆ¯Ö»Ö²¬Ö

Ûú¸üÖµÖÖ •ÖÖµÖ … ÃÖÖ£Ö Æüß ÃÛæú»ÖÖë ´Öë ¯ÖÏÖŸÖ:ÛúÖ»Öß®Ö ‹ÃÖê ²Ö»Öß Ûêú ÃÖ´ÖµÖ ²Ö““ÖÖë ÛúÖê †Ö¬Öê ‘ÖÓ™êü Ûúß ¿ÖÖ¸üß׸üÛú ÛúÃÖ¸üŸÖ

Ûú¸üÖ‡Ô •ÖÖµÖê … ”û: ´ÖÖÆü Ûêú ¯Ö¿“ÖÖŸÖË ÁÖß ¸üÖµÖ ®Öê ‹Ûú þÖÖãµÖ ×®Ö¸üßõÖÞÖ ¯Öã®Ö: Ûú¸üÖµÖÖ †Öî ü ¤êüÜÖÖ ÝÖµÖÖ ×Ûú ²Ö““ÖÖë Ûêú

þÖÖãµÖ ´Öë †®Öã Ö´Ö ÃÖã¬ÖÖ¸ü Æãü†Ö Æîü …

ˆ¯Ö¸üÖêŒŸÖ ÛúÖê ¯ÖœÌü®Öê Ûêú ²ÖÖ¤ü ×®Ö´®Ö Ûêú ˆ¢Ö¸ü ¤üßו֋ :

(i) ÁÖß ¸üÖµÖ «üÖ¸üÖ ×Ûú®Ö ´Ö滵ÖÖë (Ûú´Ö ÃÖê Ûú´Ö ¤üÖê) ÛúÖê ¤ü¿ÖÖÔµÖÖ ÝÖµÖÖ Æîü ?

(ii) ‹Ûú ×¾ÖªÖ£Öá Ûêú ºþ¯Ö ´Öë ‡ÃÖ ×¾ÖÂÖµÖ ´Öë †Ö¯Ö ÛîúÃÖê •ÖÖÝÖºþÛúŸÖÖ ±îú»ÖÖµÖëÝÖê ?

(iii) ¿ÖÖ×®ŸÖÛúÖ¸üÛú ŒµÖÖ Æïü ? ‹Ûú ˆ¤üÖÆü¸üÞÖ ¤üßו֋ …

(iv) ‹Ã¯Öî™ìü´Ö ÛúÖ ˆ¯ÖµÖÖêÝÖ ŒµÖÖë šÓü›êü ³ÖÖê•µÖ ¯Ö¤üÖ£ÖÔ †Öî ü ¯ÖêµÖ ´Öë Æüß ÃÖß×´ÖŸÖ ÆüÖêŸÖÖ Æîü ? 4

Page 230: Chemistry Past Papers

56/1/2/D 9 [P.T.O.

Mr. Roy, the principal of one reputed school organized a seminar in which he invited

parents and principals to discuss the serious issue of diabetes and depression in

students. They all resolved this issue by strictly banning the junk food in schools and

to introduce healthy snacks and drinks like soup, lassi, milk etc. in school canteens.

They also decided to make compulsory half an hour physical activities for the students

in the morning assembly daily. After six months, Mr. Roy conducted the health survey

in most of the schools and discovered a tremendous improvement in the health of

students.

After reading the above passage, answer the following :

(i) What are the values (at least two) displayed by Mr. Roy ?

(ii) As a student, how can you spread awareness about this issue ?

(iii) What are tranquilizers ? Give an example.

(iv) Why is use of aspartame limited to cold foods and drinks ?

24. †ÞÖã ÃÖæ¡Ö C7H7ON ÛúÖ ‹Ûú ‹¸üÖê Öê×™üÛú µÖÖî×ÝÖÛú ‘A’ ®Öß“Öê פüµÖê ÝÖµÖê Ûêú †®ÖãÃÖÖ¸ü ‹Ûú †×³Ö×ÛÎúµÖÖ ÀÖéÓÜÖ»ÖÖ ¤êüŸÖÖ

Æîü … ×®Ö´®Ö †×³Ö×ÛÎúµÖÖ†Öë ´Öë A, B, C, D †Öî ü E Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ : 5

An aromatic compound ‘A’ of molecular formula C7H7ON undergoes a series of

reactions as shown below. Write the structures of A, B, C, D and E in the following

reactions :

†£Ö¾ÖÖ/OR

Page 231: Chemistry Past Papers

56/1/2/D 10

24. (a) •Ö²Ö ‹×®Ö»Öß®Ö ×®Ö´®Ö †×³ÖÛúÖ¸üÛúÖë Ûêú ÃÖÖ£Ö †×³Ö×ÛÎúµÖÖ Ûú¸üŸÖÖ Æîü ŸÖ²Ö ´ÖãÜµÖ ˆŸ¯ÖÖ¤üÖë Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ ×»Ö×ÜÖ‹ :

(i) Br2 •Ö»Ö

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) ×®Ö´®Ö ÛúÖê ˆ®ÖÛêú Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²ÖœÌüŸÖê ÛÎú´Ö ´Öë ×»Ö×ÜÖ‹ :

C2H5NH2, C2H5OH, (CH3)3N

(c) ×®Ö´®Ö µÖÖî×ÝÖÛúÖë Ûêú µÖãÝ´Ö ´Öë ¯ÖÆü“ÖÖ®Ö Ûú¸ü®Öê Ûêú ×»ÖµÖê ‹Ûú ÃÖÖ´ÖÖ®µÖ ¸üÖÃÖÖµÖ×®ÖÛú •ÖÖÑ“Ö ¤üßו֋ :

(CH3)2NH †Öî ü (CH3)3N 5

(a) Write the structures of main products when aniline reacts with the following

reagents :

(i) Br2 water

(ii) HCl

(iii) (CH3CO)2O / pyridine

(b) Arrange the following in the increasing order of their boiling point :

C2H5NH2, C2H5OH, (CH3)3N

(c) Give a simple chemical test to distinguish between the following pair of

compounds :

(CH3)2NH and (CH3)3N

25. •Ö»ÖßµÖ ×¾Ö»ÖµÖ®Ö ´Öë ´Öê×£Ö»Ö ‹êÃÖß™êü™ü Ûêú •Ö»Ö-†¯Ö‘Ö™ü®Ö Ûêú ×»ÖµÖê ×®Ö´®Ö ¯Ö׸üÞÖÖ´Ö ¯ÖÏÖ¯ŸÖ ÆãüµÖê £Öê :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) פüÜÖ»ÖÖ‡‹ ×Ûú µÖÆü ‹Ûú ”û¤Ëü´Ö ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ Ûêú †®ÖãÃÖÖ¸ü Æîü ŒµÖÖë×Ûú •Ö»Ö ÛúÖ ÃÖÖÓ¦üÞÖ ×ãָü ¸üÆüŸÖÖ

Æîü …

(ii) ÃÖ´ÖµÖ 30 ÃÖê 60 ÃÖêÛúÞ›ü Ûêú ²Öß“Ö †×³Ö×ÛÎúµÖÖ Ûúß †ÖîÃÖŸÖ ¤ü¸ü ¯Ö׸üÛú×»ÖŸÖ Ûúßו֋ …

(פüµÖÖ ÝÖµÖÖ Æîü log 2 = 0.3010, log 4 = 0.6021) 5

Page 232: Chemistry Past Papers

56/1/2/D 11 [P.T.O.

For the hydrolysis of methyl acetate in aqueous solution, the following results were

obtained :

t/s 0 30 60

[CH3COOCH3]/mol L–1 0.60 0.30 0.15

(i) Show that it follows pseudo first order reaction, as the concentration of water

remains constant.

(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.

(Given log 2 = 0.3010, log 4 = 0.6021)

†£Ö¾ÖÖ/OR

25. (a) ‹Ûú †×³Ö×ÛÎúµÖÖ A + B → P Ûêú ×»ÖµÖê ¤ü¸ü ¤üß ÝÖ‡Ô Æîü

¤ü¸ü = k[A] [B]2

(i) µÖפü B ÛúÖ ÃÖÖÓ¦üÞÖ ¤üÖê ÝÖã®ÖÖ Ûú¸ü פüµÖÖ •ÖÖµÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß ¤ü¸ü ÛîúÃÖê ¯ÖϳÖÖ×¾ÖŸÖ ÆüÖêÝÖß ?

(ii) µÖפü A ²ÖÆãüŸÖ †×¬ÖÛú ´ÖÖ¡ÖÖ ´Öë ´ÖÖî•Öæ¤ü ÆüÖê ŸÖÖê †×³Ö×ÛÎúµÖÖ Ûúß Ûãú»Ö ÛúÖê×™ü ŒµÖÖ Æîü ?

(b) ‹Ûú ¯ÖÏ£Ö´Ö ÛúÖê×™ü †×³Ö×ÛÎúµÖÖ 50% ¯Öæ üß ÆüÖê®Öê ´Öë 30 ×´Ö®Ö™ü »ÖêŸÖß Æîü … ‡ÃÖ †×³Ö×ÛÎúµÖÖ ÛúÖê 90% ¯ÖæÞÖÔ ÆüÖê®Öê ´Öë

•ÖÖê ÃÖ´ÖµÖ »ÖÝÖêÝÖÖ ˆÃÖÛúÖ ¯Ö׸üÛú»Ö®Ö Ûúßו֋ …

(log 2 = 0.3010) 5

(a) For a reaction A + B → P, the rate is given by

Rate = k[A] [B]2

(i) How is the rate of reaction affected if the concentration of B is doubled ?

(ii) What is the overall order of reaction if A is present in large excess ?

(b) A first order reaction takes 30 minutes for 50% completion. Calculate the time

required for 90% completion of this reaction.

(log 2 = 0.3010)

26. (a) ×®Ö´®Ö Ûêú ÛúÖ¸üÞÖ ¤êüŸÖê Æãü‹ ïÖ™ü Ûúßו֋ :

(i) HF ÃÖê HI Ûúß †Öê ü †´»ÖßµÖ Ã¾Ö³ÖÖ¾Ö ²ÖœÌüŸÖÖ Æîü …

(ii) †ÖòŒÃÖß•Ö®Ö †Öî ü ÃÖ»±ú¸ü Ûêú ×Æü´ÖÖÓÛú †Öî ü Œ¾Ö£Ö®ÖÖÓÛú Ûêú ²Öß“Ö ²Ö›ÌüÖ †ÓŸÖ¸ü Æîü …

(iii) ®ÖÖ‡™ÒüÖê•Ö®Ö ¯Öê®™üÖÆîü»ÖÖ‡›ëü ®ÖÆüà ²Ö®ÖÖŸÖÖ Æîü …

(b) ×®Ö´®Ö Ûúß ÃÖÓ ü“Ö®ÖÖ‹Ñ †Ö êü×ÜÖŸÖ Ûúßו֋ :

(i) Cl F3

(ii) XeF4 5

Page 233: Chemistry Past Papers

56/1/2/D 12

(a) Account for the following :

(i) Acidic character increases from HF to HI.

(ii) There is large difference between the melting and boiling points of oxygen

and sulphur.

(iii) Nitrogen does not form pentahalide.

(b) Draw the structures of the following :

(i) Cl F3

(ii) XeF4

†£Ö¾ÖÖ/OR

26. (i) ±úÖòñúÖê üÃÖ ÛúÖ ÛúÖî®Ö ‹»ÖÖê™ÒüÖò Ö †×¬ÖÛú ÃÖ×ÛÎúµÖ Æîü †Öî ü ŒµÖÖë ?

(ii) ÃÖã Ö¸üÃÖÖê×®ÖÛú •Öê™ü ¯»Öê®Ö †Öê•ÖÖê®Ö ¯ÖŸÖÔ Ûêú †¾ÖõÖµÖ Ûêú ×»Ö‹ ÛîúÃÖê וִ´Öê¤üÖ¸ü Æïü ?

(iii) Cl2 Ûúß †¯ÖêõÖÖ F2 Ûúß †Ö²Ö®¬Ö ×¾ÖµÖÖê•Ö®Ö ‹®£ÖÖß Ûú´Ö ŒµÖÖë Æîü ?

(iv) ´ÖÖîÃÖ´Ö×¾Ö–ÖÖ®Ö ´Öë †¾Ö»ÖÖêÛú®Ö Ûêú ×»ÖµÖê ²Öî»Öæ®ÖÖë ´Öë ³Ö¸ü®Öê Ûêú ×»ÖµÖê ×ÛúÃÖ ˆŸÛéú™ü ÝÖîÃÖ ÛúÖ ¯ÖϵÖÖêÝÖ ×ÛúµÖÖ •ÖÖŸÖÖ

Æîü ?

(v) ×®Ö´®Ö ÃÖ´ÖßÛú¸üÞÖ ÛúÖê ¯Öæ üÖ Ûúßו֋ :

XeF2 + PF5 → 5

(i) Which allotrope of phosphorus is more reactive and why ?

(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone

layers ?

(iii) F2 has lower bond dissociation enthalpy than Cl2. Why ?

(iv) Which noble gas is used in filling balloons for meteorological observations ?

(v) Complete the equation :

XeF2 + PF5 →

_________

Page 234: Chemistry Past Papers

1

Qu

es. Value points Marks

1 3 1

2 2, 5 - dinitrophenol 1

3 CH3-CH2-Br

Because it is a primary halide / (10) halide

½ +½

4 BaCl2 because it has greater charge / +2 charge ½ +½

5 X2Y3 1

6. Elements which have partially filled d-orbital in its ground states or any one of its oxidation

states.

1) Variable oxidation states

2) Form coloured ion

Or any other two correct characteristics

1

½ +½

7. 1) Diamminedichloridoethylenediaminechromium(III) chloride

2) [Co(NH3)5(ONO)]2+

1+ 1

8. (i)LiAlH4 / NaBH4 /H2, Pt

(ii)KMnO4 , KOH

1

1

9

9.

When vapour pressure of solution is higher than that predicted by Raoult’s law /

the intermolecular attractive forces between the solute-solvent/(A-B) molecules are weaker than

those between the solute-solute and solvent-solvent molecules/A-A or B-B molecules.

Eg. ethanol-acetone/ethanol-cyclohexane/CS2-acetone or any other correct example

ΔmixH is positive OR

(a)Azeotropes are binary mixtures having the same composition in the liquid and vapour phase

and boil at a constant temperature.

(b) Minimum boiling azeotrope

eg - ethanol + water or any other example

1

½

½

1

½

½

10 (i)Ag+

(aq) + e- Ag (s)

Reaction with higher E0

value / ∆ G0

negative

(ii) Molar conductivity of a solution at infinite dilution or when concentration approaches

zero

Number of ions per unit volume decreases

½

½

½

½

CHEMISTRY MARKING SCHEME

DELHI -2015

SET -56/1/1/D

Page 235: Chemistry Past Papers

2

11

∆Tf = i Kf m

∆Tf = i Kf wb x1000

Mb x wa

1.62 K = i x 4.9K kg mol-1

x 3.9 g x 1000

122 gmol-1

49 kg

i = 0.506

Or by any other correct method

As i<1 , therefore solute gets associated.

½

1

½

1

12 (i) Zinc being low boiling will distil first leaving behind impurities/ or on electrolysis the pure

metal gets deposited on cathode from anode.

(ii)Silica acts as flux to remove iron oxide which is an impurity as slag or FeO + SiO2 FeSiO3

(iii)Wrought iron

1

1

1

13 d = z x M

a3 NA

z = d a3 NA

M

z = 2.7 g cm-3

x 6.022 x1023

mol-1

x ( 4.05 x 10-8

cm)3

27 g mol-1

= 3.999 ≈ 4

Face centered cubic cell/ fcc

½

1

½

1

14 (i) 5f orbital electrons have poor shielding effect than 4f

(ii)due to d-d transition / or the energy of excitation of an electron from lower d orbital to higher

d-orbital lies in the visible region /presence of unpaired electrons in the d-orbital.

(iii) 2 MnO4- + 6 H

+ + 5 NO2

- 2 Mn

2+ + 3 H2O + 5 NO3

-

1

1

1

15 (i)

(ii)t2 g3 e g

1

(iii) sp3 , diamagnetic

1

1

½+½

Page 236: Chemistry Past Papers

3

16 The cell reaction : Fe(s) + 2H+ (aq) Fe

2+ (aq) + H2(g)

Eocell = E

oc - E

oa

= [0-(-0.44)]V=0.44V

Ecell = Ecell - 0.059 log [ Fe2+

]

2 [ H+]2

Ecell = 0.44 V - 0.059 log ( 0.001 )

2 ( 0.01 ) 2

= 0.44 V - 0.059 log ( 10 )

2

= 0.44 V - 0.0295 V

=≈ 0.410 V

1

1

1

17 (i) mutual coagulation

(ii)strong interaction between dispersed phase and dispersion medium or solvated layer

(iii)CO acts as a poison for catalyst

1

1

1

18 (i)Hexamethylene diamine NH2 (CH2)6 NH2 and

adipic acid HOOC- (CH2)4- COOH

(ii)3 hydroxybutanoic acid CH3CH(OH)CH2COOH and

3 hydroxypentanoic acid CH3CH2CH(OH)CH2COOH

(iii)Chloroprene H2C=C(Cl)CH=CH2

IUPAC names are accepted

Note : ½ mark for name /s and ½ mark for structure / s

½

½

½

½

½

½

19

(i)CH3CH2CH3

(ii) C6H5COONa + CHI3

(iii)CH4

1

½, ½

1

20

(i) C6H5OH + NaOH C6H5ONa CH3X C6H5OCH3

Or

C6H5OH + Na C6H5ONa CH3X C6H5OCH3

(ii)CH3CH(OH)CH3 CrO3 or Cu/573K CH3COCH3 (i)CH3MgX (CH3)2C(OH)CH3

(ii)H2O

(iii)C6H5NH2 NaNO2 + HCl C6H5N2Cl H2O warm C6H5OH

273K

1

1

1

o

Page 237: Chemistry Past Papers

4

20

OR

a)

b)

(Acetyl chloride instead of acetic anhydride may be used)

½

½

1

1

21 (i)Maltose

(ii) fibrous proteins: parallel polypeptide chain , insoluble in water

Globular proteins: spherical shape, soluble in water, (or any 1 suitable difference)

(iii) Vitamin D

1

1

1

22 (i)Larger surface area, higher van der Waals’ forces , higher the boiling point

(ii)Rotation due to one enantiomer is cancelled by another enantiomer

(iii) - NO2 acts as Electron withdrawing group or –I effect

1

1

1

23 (i) Concern for students health, Application of knowledge of chemistry to daily life,

empathy , caring or any other

(ii)Through posters, nukkad natak in community, social media, play in assembly or any other

(iii)Tranquilizers are drugs used for treatment of stress or mild and severe mental disorders .. Eg:

equanil (or any other suitable example)

(iv) Aspartame is unstable at cooking temperature.

½, ½

1

½ , ½

1

24

(a) (i) Due to decrease in bond dissociation enthalpy from HF to HI , there is an increase in acidic

character observed.

(ii)Oxygen exists as diatomic O2 molecule while sulphur as polyatomic S8

(iii)Due to non availability of d orbitals

1

1

1

Page 238: Chemistry Past Papers

5

24

(b)

OR

(i) White Phosphorus because it is less stable due to angular strain

(ii)Nitrogen oxides emitted by supersonic jet planes are responsible for depletion of ozone layer.

Or NO+O3 NO2+ O2

(iii)due to small size of F, large inter electronic repulsion / electron- electron repulsion among the

lone pairs of fluorine

(iv)Helium

(v) XeF2 + PF5 [XeF]+ [PF6]

-

1

1

½ , ½

1

1

1

1

25

25

A = B = C = D = E =

OR

O

a. i)

ii) iii)

b. ( CH3)3N < C2H5NH2 < C2H5OH

c. By Hinsberg test secondary amines ( CH3)2NH shows ppt formation which is insoluble in

KOH

while

tertiary amines ( CH3)3N do not react with benzene sulphonyl choride

1x5

= 5

1

1

1

1

1

Page 239: Chemistry Past Papers

6

26

26

(a)

k = 2.303 log [ A0 ]

t [A]

k = 2.303 log 0.60

30 0.30

k = 2.303 x 0.301 = 0.023 s-1

30

k = 2.303 log 0.60

60 0.15

k = 2.303 x 0.6021 = 0.023 s-1

60

As k is constant in both the readings, hence it is a pseudofirst order reaction.

ii)

Rate = - Δ[R]/Δt

= -[0.15-0.30]

60-30

= 0.005 mol L-1

s-1

OR

a)

(i) Rate will increase 4 times of the actual rate of reaction.

(ii) Second order reaction

b) t

1/2 = 0.693

k

30min =

0.693

k

k = 0.0231min-1

1

½

½

1

½

½

1

1+1

½

½

Page 240: Chemistry Past Papers

7

k = 2.303 log [ A0 ]

t [A]

t = 2.303 log 100

0.0231 10

t = 2.303 min

0.0231

t = 99.7min

½

½

1

Page 241: Chemistry Past Papers

56/2/1 1 P.T.O.

narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð >na Adí` bIo§ & Candidates must write the Code on the

title page of the answer-book.

Series OSR/2 H$moS> Z§. 56/2/1

Code No.

amob Z§. Roll No.

agm`Z dkmZ (g¡ÕmpÝVH$) CHEMISTRY (Theory)

ZYm©[aV g_` : 3 KÊQ>o AYH$V_ A§H$ : 70

Time allowed : 3 hours Maximum Marks : 70

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _o§ _wÐV n¥ð> 15 h¢ &

àíZ-nÌ _| XmhZo hmW H$s Amoa XE JE H$moS >Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na bI| &

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _| >30 àíZ h¢ &

H¥$n`m àíZ H$m CÎma bIZm ewê$ H$aZo go nhbo, àíZ H$m H«$_m§H$ Adí` bI| & Bg àíZ-nÌ H$mo n‹T>Zo Ho$ bE 15 _ZQ >H$m g_` X`m J`m h¡ & àíZ-nÌ H$m dVaU nydm©•

_| 10.15 ~Oo H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg AdY Ho$ Xm¡amZ do CÎma-nwpñVH$m na H$moB© CÎma Zht bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

Please check that this question paper contains 30 questions.

Please write down the Serial Number of the question before

attempting it.

15 minutes time has been allotted to read this question paper. The question

paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

Page 242: Chemistry Past Papers

56/2/1 2

gm_mÝ` ZXe :

(i) g^r àíZ AZdm`© h¢ &

(ii) àíZ-g§»`m 1 go 8 VH$ AV bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 1 A§H$ h¡ &

(iii) àíZ-g§»`m 9 go 18 VH$ bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 2 A§H$ h¡§ &

(iv) àíZ-g§»`m 19 go 27 VH$ ^r bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 3 A§H$ h¢ &

(v) àíZ-g§»`m 28 go 30 VH$ XrK©-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 5 A§H$ h¢ &

(vi) Amdí`H$VmZwgma bm°J Q>o~bm| H$m à`moJ H$a| & H¡$ëHw$boQ>am| Ho$ Cn`moJ H$s AZw_V Zht h¡ &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 8 are very short-answer questions and carry

1 mark each.

(iii) Questions number 9 to 18 are short-answer questions and carry 2 marks

each.

(iv) Questions number 19 to 27 are also short-answer questions and carry

3 marks each.

(v) Questions number 28 to 30 are long-answer questions and carry 5 marks

each.

(vi) Use Log Tables, if necessary. Use of calculators is not allowed.

1. \o$Z ßbdZ dY _| A`ñH$m| H$mo gmÝÐV H$aZo _| g§J«mhH$m| (collectors) H$m Š`m H$m © hmoVm

h¡ ? 1

What is the function of collectors in the froth floatation process for the

concentration of ores ?

2. ^m¡VH$ AYemofU hmoZo _| H$g àH$ma Ho$ ~b CÎmaXm`r hmoVo h¢ ? 1

What type of forces are responsible for the occurrence of physisorption ?

Page 243: Chemistry Past Papers

56/2/1 3 P.T.O.

3. EH$b N – N Am~ÝY EH$b P – P Am~ÝY go Xþ~©b Š`m| hmoVm h¡ ? 1

Why is the single N – N bond weaker than the single P – P bond ?

4. ZåZbIV g§H$a H$g àH$ma H$s g_md`dVm (isomerism) àXe©V H$aVm h¡ : 1

[Co(NH3)6][Cr(CN)6]

What type of isomerism is shown by the following complex :

[Co(NH3)6][Cr(CN)6]

5. b.c.c. EoH$H$ gob _| na_mUw ÌÁ`m (r) Am¡a gob Ho$ H$Zmao H$s bå~mB© (a) Ho$ Amngr

gå~ÝY H$mo ì`º$ H$sOE & 1

Express the relationship between atomic radius (r) and the edge

length (a) in the b.c.c. unit cell.

6. ZåZbIV `m¡JH$ H$m AmB©.`y.nr.E.gr. (IUPAC) Zm_ bIE : 1

Write the IUPAC name of the following compound :

7. BZ XmoZm| _| go H$m¡Z-gm AYH$ jmar` h¡ Am¡a Š`m| ? 1

Which of the two is more basic and why ?

8. ñQ>mM© ~ZmZo dmbo -½byH$moµO Ho$ Xmo KQ>H$m| Ho$ Zm_ bIE & 1

Name the two components of -glucose which constitute starch.

Page 244: Chemistry Past Papers

56/2/1 4

9. Ni(NO3)2 Ho$ EH$ db`Z H$m ßb¡Q>Z_ Ho$ BboŠQ´>moS>m| Ho$ ~rM 5.0 Eoånr`a dÚwV² Ymam go

20 _ZQ> VH$ d¡ÚwV AnKQ>Z H$`m J`m & H¡$WmoS> na ZH¡$b H$m H$VZm Ðì`_mZ ZjonV

hmoJm ? 2

(X`m J`m h¡ : ZH¡$b H$m na_mUw Ðì`_mZ = 58.7 g mol–1, 1 F = 96500 C mol–1)

A solution of Ni(NO3)2 is electrolysed between platinum electrodes using

a current of 5.0 ampere for 20 minutes. What mass of nickel will be

deposited at the cathode ?

(Given : At. Mass of Ni = 58.7 g mol–1, 1 F = 96500 C mol–1)

10. A^H«$`m H$s AY© Am`w H$s n[a^mfm bIE & ZåZ Ho$ AY© Am`w Ho$ b o ì`§OH$ bIE : 2

(i) eyÝ` H$moQ> H$s A^H«$`m

(ii) àW_ H$moQ> H$s A^H«$`m

Define half-life of a reaction. Write the expression of half-life for

(i) zero order reaction and

(ii) first order reaction.

11. gëda A`ñH$ go gëda Ho$ ZîH$f©U go gå~Õ amgm`ZH$ A^H«$`mE± bIE & 2

Write the chemical reactions involved in the extraction of silver from

silver ore.

12. gëµ\$a Ho$ Xmo AV _hÎdnyU© Anaê$nm| Ho$ Zm_ bIE & BZ XmoZm| _| go H$m¡Z-gm H$j Vmn

na ñWm`r hmoVm h¡ ? Š`m hmoVm h¡ O~ ñWm`r ê$n H$mo 370 K go D$na Ja_ H$`m OmVm h¡ ? 2

AWdm

(i) gånH©$ dY go H2SO4 H$s àmá H$mo AYH$V_ ~ZmZo Ho$ àV~ÝY bIE &

(ii) Ob _§o H2SO4 Ho$ bE Ka2 << Ka1 Š`m| h¡ ? 2

Page 245: Chemistry Past Papers

56/2/1 5 P.T.O.

Name the two most important allotropes of sulphur. Which one of the two

is stable at room temperature ? What happens when the stable form is

heated above 370 K ?

OR

(i) Write the conditions to maximize the yield of H2SO4 by contact

process.

(ii) Why is Ka2 << Ka1 for H2SO4 in water ?

13. ZåZ g_rH$aUm| H$mo nyam H$sOE : 2

(i) –

4MnO2 + 5 S2– + 16 H+

(ii) –2

72OCr + 2 OH– 2

Complete the following equations :

(i) –

4MnO2 + 5 S2– + 16 H+

(ii) –2

72OCr + 2 OH–

14. g§H$a [CoF6]3 – Ho$ b o g§H$aU AdñWm, AmH¥$V Am¡a IUPAC Zm_ bIE & 2

(Co H$m na_mUw H«$_m§H$ = 27)

Write the state of hybridization, shape and IUPAC name of the complex

[CoF6]3 –. (Atomic no. of Co = 27)

15. ZåZ Ho$ bE amgm`ZH$ g_rH$aU bIE : 2

(i) O~ EWb ŠbmoamBS> H$s Obr` KOH go A^H«$`m H$s OmVr h¡ &

(ii) O~ ZO©b AlCl3 H$s CnpñWV _| Šbmoamo~oݵOrZ H$s CH3COCl go A^H«$`m H$s OmVr h¡ &

Write chemical equations when

(i) ethyl chloride is treated with aqueous KOH.

(ii) chlorobenzene is treated with CH3COCl in presence of anhydrous

AlCl3.

Page 246: Chemistry Past Papers

56/2/1 6

16. (a) ZåZ `w½_m| go H$g EopëH$b hobmBS> H$s Amn SN2 H«$`mdY Ûmam AYH$ Vrd«Vm go A^H«$`m H$aZo H$s Amem H$a|Jo Am¡a Š`m| ? CH3 – CH2 – CH – CH3 CH3 – CH2 – CH2 – CH2 – Br

Br

(b) SN1 A^H«$`mAm| _| aog_rH$aU hmo OmVm h¡ & Š`m| ? 2

(a) Which alkyl halide from the following pairs would you expect to

react more rapidly by an SN2 mechanism and why ?

CH3 – CH2 – CH – CH3 CH3 – CH2 – CH2 – CH2 – Br

Br

(b) Racemisation occurs in SN1 reactions. Why ?

17. ZåZ A^H«$`m H$s H«$`mdY bIE : 2

OHBrCHCHHBr

OHCHCH 22323

Write the mechanism of the following reaction :

OHBrCHCHHBr

OHCHCH 22323

18. ZåZ A^H«$`mAm| _| à`wº$ A^H$maH$m| Ho$ Zm_ bIE : 2

(i) µ\$sZm°b Ho$ ~«mo_rZoeZ go 2,4,6-Q´>mB©~«mo_moµ\$sZm°b ~ZmZm

(ii) ã`yQ>oZ-2-AmoZ go ã`yQ>oZ-2-Amob ~ZmZm

(iii) EoZgmob H$m \«$sS>ob – H«$mµâQ²>g EopëH$brH$aU

(iv) àmW_H$ EoëH$mohm°b Ho$ Am°ŠgrH$aU Ûmam H$m~m©opŠgbH$ Aåb ~ZmZm

Name the reagents used in the following reactions :

(i) Bromination of phenol to 2,4,6-tribromophenol

(ii) Butan-2-one to Butan-2-ol

(iii) Friedel − Crafts alkylation of anisole

(iv) Oxidation of primary alcohol to carboxylic acid

Page 247: Chemistry Past Papers

56/2/1 7 P.T.O.

19. (i) KCl H$g àH$ma H$m agg_rH$aU_Vr` Xmof XImVm h¡ Am¡a Š`m| ?

(ii) gbH$m°Z H$mo As go S>monV H$aZo na H$g àH$ma H$m AY©MmbH$ ~ZVm h¡ ?

(iii) ZåZ _| go H$m¡Z-gm AmpÊdH$ R>mog H$m CXmhaU h¡ : CO2 AWdm SiO2

(iv) BZ_| go H$m¡Z-gm AYH$ AÀN>o Mwå~H$ ~ZmEJm, \o$amoMwå~H$s` nXmW© AWdm \o$arMwå~H$s` nXmW© ? 3

(i) What type of stoichiometric defect is shown by KCl and why ?

(ii) What type of semiconductor is formed when silicon is doped with

As ?

(iii) Which one of the following is an example of molecular solid :

CO2 or SiO2

(iv) What type of substances would make better magnets,

ferromagnetic or ferrimagnetic ?

20. (i) gmYmaU gob H$s VwbZm _| H2 – O2 BªYZ gob Ho$ Xmo bm^ bIE &

(ii) ZrMo Xr JB© gob A^H«$`m Ho$ b o gmå` pñWam§H$ (Kc) 10 h¡ & BgHo$ b o oE

gob

n[aH$bV H$sOE &

3

(i) Write two advantages of H2 – O2 fuel cell over ordinary cell.

(ii) Equilibrium constant (Kc) for the given cell reaction is 10.

CalculateocellE .

Page 248: Chemistry Past Papers

56/2/1 8

21. pñWa Am`VZ AdñWm _| SO2Cl2 Ho$ àW_ H$moQ> Ho$ D$î_r` AnKQ>Z _| ZåZ Am§H$‹S>oo àmá

hþE Wo :

)g(Cl)g(SO)g(ClSO 2222

à`moJ g_`/s−1 gH$b Xm~/atm

1 0 0.4

2 100 0.7

doJ pñWam§H$ n[aH$bV H$sOE & (X`m J`m h¡ : log 4 = 0.6021, log 2 = 0.3010) 3

The following data were obtained during the first order thermal

decomposition of SO2Cl2 at a constant volume :

)g(Cl)g(SO)g(ClSO 2222

Experiment Time/s−1 Total pressure/atm

1 0 0.4

2 100 0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

22. (a) R>mogm| na J¡gm| Ho$ AYemofU Ho$ bE \«$m° ÝS>bH$ AYemofU g_Vmnr (isotherm) Ho$ bE EH$ g_rH$aU Ho$ ê$n _| ì`§OH$ bIE &

(b) _ŠIZ Ho$ n[ajá àmdñWm Am¡a n[ajon _mÜ`_ Š`m h¢ ?

(c) g_wÐ Am¡a ZXr Ho$ _bZo Ho$ ñWmZ na S>oëQ>m ~ZVm h¡ & Š`m| ? 3

(a) Write the expression for the Freundlich adsorption isotherm for

the adsorption of gases on solids, in the form of an equation.

(b) What are the dispersed phase and dispersion medium of butter ?

(c) A delta is formed at the meeting place of sea and river water.

Why ?

Page 249: Chemistry Past Papers

56/2/1 9 P.T.O.

23. (a) b¡ÝWoZm°`S> H$m¡Z-H$m¡Z gr d^Þ CnMm`r AdñWmE± XImVo h¢ ?

(b) g§H«$_U VÎdm| H$s Xmo deofVmE± bIE &

(c) 3d-ãbm°H$ Ho$ VÎdm| _| go H$Z-H$Z H$mo g§H«$_U VÎd Zht _mZm Om gH$Vm h¡ Am¡a Š`m| ? 3

AWdm

ZåZ Ho$ bE Cn wº$ H$maU bIE :

(a) AnZr +3 Am°ŠgrH$aU AdñWm H$mo àmá H$aZo Ho$ bE Fe2+ `m¡JH$mo§ H$s VwbZm _| Mn2+ `m¡JH$ AYH$ ñWm`r hmoVo h¢ &

(b) Sc (Z = 21) go Zn (Z = 30) VH$ Ho$ 3d grarµO Ho$ VÎdm| _| go Zn H$s na_mUwH$aU H$s EoÝW¡ënr g~go H$_ hmoVr h¡ &

(c) Obr` db`Z _|o Sc3+ a§JhrZ hmoVm h¡ O~H$ Ti3+ a§JrZ hmoVm h¡ & 3

(a) What are the different oxidation states exhibited by the

lanthanoids ?

(b) Write two characteristics of the transition elements.

(c) Which of the 3d-block elements may not be regarded as the

transition elements and why ?

OR

Assign suitable reasons for the following :

(a) The Mn2+ compounds are more stable than Fe2+ towards oxidation

to their +3 state.

(b) In the 3d series from Sc (Z = 21) to Zn (Z = 30), the enthalpy of

atomization of Zn is the lowest.

(c) Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.

Page 250: Chemistry Past Papers

56/2/1 10

24. ZåZ A^H«$`mAm| _| A, B Am¡a C H$s g§aMZmE± ~VmBE : 3

(i) K273

CHNO

BLiAlH

AKCN

BrCH 243

(ii)

CNaOHCHCl

BKOHBr

ANH

COOHCH 3233

Give the structures of A, B and C in the following reactions :

(i) K273

CHNO

BLiAlH

AKCN

BrCH 243

(ii)

CNaOHCHCl

BKOHBr

ANH

COOHCH 3233

25. ZåZ nXm| H$s n[a^mfmE± bIE : 3 (a) EoZmo_a

(b) àmoQ>rZm| H$m dH¥$VrH$aU

(c) Amdí`H$ Eo_rZmoo Aåb

Define the following terms :

(a) Anomers

(b) Denaturation of proteins

(c) Essential amino acids

26. (i) EoÝQ>rhñQ>m_rZ H$s EH$ CXmhaU ghV n[a^mfm bIE &

(ii) ZåZ Am¡fY`m| _| go H$m¡Z-gr àVO¡dH$ h¡ :

_m°\$s©Z, BŠdmZb, ŠbmoaEoåµ\¡$ZH$mob, Eopñn[aZ &

(iii) EoñnmQ>©o_ H$m Cn`moJ R>§S>o ^moOZ Am¡a no` nXmWmªo VH$ gr_V Š`m| hmoVm h¡ ? 3

(i) Define Antihistamine with an example.

(ii) Which one of the following drugs is an antibiotic :

Morphine, Equanil, Chloramphenicol, Aspirin.

(iii) Why is use of aspartame limited to cold food and drink ?

Page 251: Chemistry Past Papers

56/2/1 11 P.T.O.

27. ßbmpñQ>>H$ Ho$ W¡bm| na àV~ÝY bJ OmZo Ho$ CnamÝV, EH$ ñHy$b Ho$ N>mÌm| Zo ZU© b`m H$

dh bmoJm| H$mo dmVmdaU Am¡a `_wZm ZXr na ßbmpñQ>>H$ Ho$ W¡bm| Ho$ hmZH$maH$ à^mdm| go

gyMV H$a|Jo & ~mV H$mo AYH$ à^mdr ~ZmZo Ho$ bE, CÝhm|Zo Xÿgao ñHy$bm| Ho$ gmW _bH$a

EH$ a¡br aMr Am¡a gpãµO`m± ~oMZo dmbm|, XþH$mZXmam| Am¡a S>nmQ>©_oÝQ>b ñQ>moam| _| H$mµJµO Ho$

W¡bo ~m±Q>o & g^r N>mÌm| Zo àU H$`m H$ do `_wZm ZXr H$mo ~MmZo Ho$ bE ^dî` _| nm°brWrZ

Ho$ W¡bm| H$m à`moJ Zht H$a|Jo &

Cn w©º$ boIm§e H$mo n‹T>H$a ZåZ àíZm| Ho$ CÎma XrOE : 3

(i) N>mÌm|§o Zo H$Z _yë`m| H$mo Xem©`m h¡ ?

(ii) O¡d-ZåZrH$aUr` ~hþbH$ Š`m hmoVo h¢ ? EH$ CXmhaU XrOE &

(iii) Š`m nm°brWrZ EH$ g_ (hmo_mo) ~hþbH$ h¡ AWdm gh (co-) ~hþbH$ h¡ ?

After the ban on plastic bags, students of one school decided to create

awareness among the people about the harmful effects of plastic bags on

the environment and the Yamuna river. To make it more impactful, they

organized a rally by joining hands with other schools and distributed

paper bags to vegetable vendors, shopkeepers and departmental stores.

All students pledged not to use polythene bags in future to save the

Yamuna river.

After reading the above passage, answer the following questions :

(i) What values are shown by the students ?

(ii) What are biodegradable polymers ? Give one example.

(iii) Is polythene a homopolymer or copolymer ?

Page 252: Chemistry Past Papers

56/2/1 12

28. (a) dmînerb Ad`dm| dmbo db`Z Ho$ bE amCëQ> Z`_ bIE & g^r gmÝÐUm|o Am¡a VmnH«$_m| na amCëQ> Z`_ AZwgma ahZo dmbo db`Z H$m Zm_ bIE & 2

(b) 200 g Ob _| 10 g CaCl2 KmobZo go àmá hþE db`Z Ho$ bE ŠdWZm§H$ CÞ`Z H$mo n[aH$bV H$sOE & (Ob Ho$ bE Kb = 0.512 K kg mol–1,

CaCl2 H$m _moba Ðì`_mZ = 111 g mol–1) 3

AWdm

(a) ZåZ nXm| H$s n[a^mfmE± bIE : 3

(i) pñWaŠdmWr (EoµO`moQ´>mon)

(ii) namgaUr (Amog_m°Q>H$) Xm~

(iii) AUwg§»` (H$mobJoQ>d) JwUY_©

(b) 9.8% (w/w) H2SO4 Ho$ db`Z H$s _mobaVm n[aH$bV H$sOE `X Bg db`Z

H$m KZËd 1.02 g ml–1 hmo & (H2SO4 H$m _moba Ðì`_mZ = 98 g mol–1) 2

(a) State Raoult’s law for a solution containing volatile components.

Name the solution which follows Raoult’s law at all concentrations

and temperatures.

(b) Calculate the boiling point elevation for a solution prepared by

adding 10 g of CaCl2 to 200 g of water. (Kb for water =

0.512 K kg mol–1, Molar mass of CaCl2 = 111 g mol–1)

OR

(a) Define the following terms :

(i) Azeotrope

(ii) Osmotic pressure

(iii) Colligative properties

(b) Calculate the molarity of 9.8% (w/w) solution of H2SO4 if the density

of the solution is 1.02 g ml–1. (Molar mass of H2SO4 = 98 g mol–1)

Page 253: Chemistry Past Papers

56/2/1 13 P.T.O.

29. (a) ZåZ Ho$ H$maU ~VmBE : 3

(i) + 5 AdñWm _| Bi à~b CnMm`H$ hmoVm h¡ &

(ii) PCl5 Vmo OmZm OmVm h¡ naÝVw NCl5 Zht &

(iii) bm¡h HCl _| KwbH$a FeCl2 ~ZmVm h¡, FeCl3 Zht &

(b) ZåZ H$s g§aMZmE± ~ZmBE : 2

(i) XeOF4

(ii) HClO4

AWdm

(a) ZåZ H$s g§aMZmE± ~ZmBE : 2

(i) H2S2O8

(ii) bmb P4

(b) ZåZ Ho$ H$maU bIE : 3

(i) dmîn AdñWm _| JÝYH$ (gë\$a) AZwMwå~H$Ëd àXe©V H$aVm h¡ &

(ii) µOrZm°Z go ^Þ, hrb`_ H$m H$moB© ñnîQ amgm`ZH$> `m¡JH$ kmV Zht h¡ &

(iii) H3PO3 go H3PO2 EH$ AYH$ à~b AnMm`H$ h¡ &

(a) Account for the following :

(i) Bi is a strong oxidizing agent in the + 5 state.

(ii) PCl5 is known but NCl5 is not known.

(iii) Iron dissolves in HCl to form FeCl2 and not FeCl3.

(b) Draw the structures of the following :

(i) XeOF4

(ii) HClO4

OR

(a) Draw the structures of the following :

(i) H2S2O8

(ii) Red P4

Page 254: Chemistry Past Papers

56/2/1 14

(b) Account for the following :

(i) Sulphur in vapour state exhibits paramagnetism.

(ii) Unlike xenon, no distinct chemical compound of helium is

known.

(iii) H3PO2 is a stronger reducing agent than H3PO3.

30. (a) EoWoZ¡b Ho$ ZåZ A^H$maH$m| Ho$ gmW A^H«$`m H$aZo na ~Zo CËnmXm| H$mo bIE : 3

(i) CH3MgBr go Am¡a \$a H3O+ go

(ii) Zn-Hg/gmÝÐ HCl go

(iii) VZw NaOH H$s CnpñWV _| C6H5CHO go

(b) ZåZ `m¡JH$ `w½_m§o _| nañna ^oX H$aZo Ho$ bE gab amgm`ZH$ narjU XrOE : 2

(i) ~oݵOmoBH$ Aåb Am¡a EWb ~oݵOmoEQ>

(ii) àmonoZ¡b Am¡a ã`yQ>oZ-2-AmoZ

AWdm

(a) ZåZ Ho$ H$maU bIE : 2

(i) HCN Ho$ gmW A^H«$`m H$aZo _| CH3COCH3 go CH3CHO AYH$ A^H«$`merb hmoVm h¡ &

(ii) go_rH$m~©oµOmBS> (H2NNHCONH2) _| Xmo –NH2 J«wn hmoVo h¢ & \$a ^r go_rH$m~m©µOmoZ ~ZmZo _| Ho$db EH$ – NH2 J«wn H«$`mH$mar hmoVm h¡ &

(b) ZåZ Zm_Ymar A^H«$`mAmo§ Ho$ bE amgm`ZH$ g_rH$aU bIE : 3

(i) amoµOoZ_wÝS A^H«$`m

(ii) hob-dmobmS>©-µOobÝñH$s A^H«$`m

(iii) H¡$ZrµOmamo A^H«$`m

(a) Write the products formed when ethanal reacts with the following

reagents :

(i) CH3MgBr and then H3O+

(ii) Zn-Hg/conc. HCl

(iii) C6H5CHO in the presence of dilute NaOH

Page 255: Chemistry Past Papers

56/2/1 15 P.T.O.

(b) Give simple chemical tests to distinguish between the following

pairs of compounds :

(i) Benzoic acid and Ethyl benzoate

(ii) Propanal and Butan-2-one

OR

(a) Account for the following :

(i) CH3CHO is more reactive than CH3COCH3 towards reaction

with HCN.

(ii) There are two – NH2 groups in semicarbazide

(H2NNHCONH2). However, only one is involved in the

formation of semicarbazone.

(b) Write the chemical equation to illustrate each of the following

name reactions :

(i) Rosenmund reduction

(ii) Hell-Volhard-Zelinsky reaction

(iii) Cannizzaro reaction

2,800

Page 256: Chemistry Past Papers

1

MARKING SCHEME

Chemistry – 2014

FOREIGN – SET (56/2/1)

1 Collectors enhance non-wettability of the mineral/ore particles 1

2 van der Waals forces 1

3 Because of high inter-electronic repulsion of non bonding electrons owing to the small

bond length / atomic size

1

4 Coordination isomerism 1

5 r=

√3

4 a or 4r =√3 a

1

6 2 – hydroxybenzaldehyde 1

7 CH3 – NH2 ,because of the electron releasing (+I effect) tendency of methyl group ½+½

8 Amylose and amylopectin 1

9 m= z I t I=5 A t= 20 x 60s = 1200s

m= atomicmass

nxF x I x t

m=.

2x96500C x 5 A x 1200 s

m= 1.825 g (or any other suitable method)

½

½

1

10 Half-life of a reaction is the time in which the concentration of a reactant is reduced

to half of its initial concentration.

(i) (ii)

1

½+½

11 4Ag + 8 CN- + 2H2O + O2 → 4 [Ag(CN)2]

- + 4 OH

-

2[Ag(CN)2] - + Zn → [Zn(CN)4]

- 2 + 2Ag

Or

Ag2S + 4NaCN → 2 Na[Ag(CN)2] + Na2S

2Na[Ag(CN)2] + Zn → Na2 [Zn(CN)4] + 2Ag

(balancing of equation is not necessary)

1

1

12 Rhombic and Monoclinic

Rhombic Sulphur

Rhombic sulphur changes to monoclinic sulphur

1

½

½

OR

12 a) High pressure and low temperature

b) Because ionization of HSO-4 is difficult / removal of proton from negatively

charged HSO-4 is difficult.

1

1

13 (i)

(ii)

1

1

14 Hydridization : sp3d

2 shape– octahedral

IUPAC – hexafluoridocobaltate(III)

½+½

1

15 (i) CH3 CH2- Cl + KOH (aq) → CH3 CH2 –OH +KCl

(ii)

1

Page 257: Chemistry Past Papers

2

1

16 a) 1-Bromobutane / CH3 CH2 CH2 CH2Br

Because it is a primary alkyl halide

b) Because carbocation formed in SN1 reaction is sp2 hybridized and planar.

½+½

1

17 HBr → H+ + Br-

Or

( where R = -CH3)

½

½

1

18 (i) Br2 / H2O or aq. Br2

(ii) LiAlH4 or NaBH4 or H2 / Ni (or any other)

(iii) R – Cl and anhyd . Al Cl3

(iv) Acidic or alkaline KMnO4, K2Cr2 O7 (acidic)

½x4=2

19 (i) Schottky defect, due to similar size of K+

and Cl-

ion

(ii) n-type

(iii) CO2

(iv) Ferromagnetic

½ +½

1

½

½

20 a)

(i) The fuel cell runs continuously as long as the reactants are supplied

(ii) Highly efficient

(iii) Pollution free

(any two)

b) log Kc = nE0cell

0.059

log Kc = 2xE0cell

0.059

log 10 =2xE0cell

0.059 [log 10 = 1]

E0

cell = 0.059

2 = 0.0295 V

½

½

½

½

Page 258: Chemistry Past Papers

3

1

21 SO2 Cl2 → SO2 + Cl2

At t = 0s 0.4 atm 0 atm 0 atm

At t = 100s (0.4 – x) atm x atm x atm

Pt = 0.4 – x + x + x

Pt = 0.4 + x

0.7 = 0.4 + x

x = 0.3

k = 2.303

t log

#$

%#$&#'

k = 2.303

t log

0.4

0.8-0.7

k = 2.303

100 log

0.4

0.1

k = %.,-,

.-- x 0.6021 = 1.39 x 10

-2 s

-1

1

1

1

22 a) /

= k p

1/n or log (x/m)= log k + 1/n log p

b) Dispersed phase = liquid Dispersion medium = Solid

c) Because of coagulation of colloidal particles

1

1

1

23 a) +3 +2 +4 oxidation states

b) Transition elements

(i) Form coloured compounds

(ii) Form complexes

(iii) Act as catalysts

(iv) Paramagnetic

(v) Form alloys

(vi) Form interstitial compounds (any two)

Or any other

c) Zn, because of fully filled d orbitals

1

½+½

½+½

OR

23 a) Because of stable half filled orbitals (3d5)

b) Because Zn has no unpaired electrons in d orbitals.

c) Because of the presence of one unpaired electron in Ti3+

whereas there is

no unpaired electron in Sc+3

1

1

1

24 (i) A = CH3CN B = CH3CH2NH2 C = CH3CH2OH

(ii) A = CH3 CONH2 B = CH3NH2 C = CH3NC

½+½+½

½+½+½

25 (i) Anomers – are the isomers which differ only in the configuration of

hydroxyl group at C-1 of glucose

Or

∝ and 1 forms of glucose are called anomers

(ii) Denaturation of proteins – when native protein is subjected to physical

or chemical change, it loses its biological activity and is called

denaturation.

(iii) Essential amino acids are the amino acids required in our diet for the

growth of the body / which are not synthesized by our body and

1

1

1

Page 259: Chemistry Past Papers

4

obtained through diet.

26 (i) The drugs which are used to prevent the interaction of histamine with

the receptors present in the stomach wall. Eg. Cimetidine / Ranitidine /

Dimetapp (or any other)

(ii) Chloramphenicol

(iii) Because it is unstable at cooking temperature

½+½

1

1

27 (i) Concern towards environment / caring / socially aware / team work.

(atleast two values)

(ii) Polymers which can be degraded by the action of microorganisms. Eg.

PHBV , Nylon -2-nylon- 6/ any natural polymer

(iii) Homo polymer

1

½+½

1

28 (i) Raoult’s law : state that for a solution containing volatile components,

the partial vapour pressure of each component is directly proportional

to its mole fraction.

Ideal solution.

(ii) ∆ Tb = i Kb xWcacl2

Mcacl2 x

.---

5678

= 3x0.512 K kg mol-1

x .-

... x

1000

200kg

= 0.69K or 0.690C

1

1

1

1

1

OR

28 a)

(i) Azeotrope is a liquid mixture which boils at constant temperature with

constant composition.

(ii) Osmotic pressure : is the pressure applied on the solution side to stop

the flow of solvent across the semi permeable membrane from lower

concentration of the solution to higher concentration.

(iii) Colligative properties : are the properties of solution which depend upon

the no of moles of solute or concentration of solute and not on the

nature of solute.

b) M =;<

V(L)= 5<

< x

1000

V(A) (B→ Solute)

M = B.

B x .---

.-- x 1.02

M = 1.02M

1

1

1

½

½

1

29 a) (i) Because Bi is more stable in +3 oxidation state.

(ii) Because of the availability to d orbital in P which is not in N/ nitrogen

cannot extend its covalency beyond 4

(iii) Because of the formation of H2(g) which prevents the oxidation of Fe+2

to

Fe+3

/ HCl is only a mild oxidising agent

a) (i) (ii)

1x3=3

1+1

Page 260: Chemistry Past Papers

5

OR

29 a) (i)

(ii)

Polymeric

b)

(i) Because of the presence of two unpaired electrons .

(ii) Because of high ionization enthalpy of He.

(iii) Because of the presence of two P-H bonds in H3PO2 whereas in

H3PO3 one P-H bond is present.

1

1

1

1

1

30 a)

(i)

CH3-CHO CH3MgBr CH3CH(CH3)- OMgBr H3O+

CH3CH(OH)- CH3

(ii) CH3CHO Zn-Hg CH3-CH3

Conc HCl

(iii) C6H5CHO + CH3-CHO dil NaOH C6H5CH(OH) CH2CHO

(Award full marks even if only products are given)

b) (i) Add NaHCO3, benzoic acid will give brisk effervescence whereas ethyl benzoate

will not give this test. (or any other test)

(ii) Add tollen’s reagent , propanal will give silver mirror whereas Butan-2-one will

not give this test. (or any other test)

1

1

1

1

1

OR

30 a) (i) Because the positve charge on carbonyl carbon of CH3 CHO decreases to a lesser

extent due to one electron releasing (+I effect) CH3 group as compared to CH3 COCH3

(two electron releasing CH3 groups) and hence more reactive.

(ii) because one of the –NH2 is involved in resonance with carbonyl group and hence

acquires positive charge.

(b) (i)

1

1

1

Page 261: Chemistry Past Papers

6

(ii)

(iii)

(or any other suitable reaction)

1

1

Page 262: Chemistry Past Papers

56/1 1 P.T.O.

narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð >na Adí` bIo§ & Candidates must write the Code on the

title page of the answer-book.

Series OSR H$moS> Z§. 56/1

Code No.

amob Z§. Roll No.

agm`Z dkmZ (g¡ÕmpÝVH$) CHEMISTRY (Theory)

ZYm©[aV g_` : 3 KÊQ>o AYH$V_ A§H$ : 70

Time allowed : 3 hours Maximum Marks : 70

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _o§ _wÐV n¥ð> 15 h¢ &

àíZ-nÌ _| XmhZo hmW H$s Amoa XE JE H$moS >Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na bI| &

H¥$n`m Om±M H$a b| H$ Bg àíZ-nÌ _| >30 àíZ h¢ &

H¥$n`m àíZ H$m CÎma bIZm ewê$ H$aZo go nhbo, àíZ H$m H«$_m§H$ Adí` bI| & Bg àíZ-nÌ H$mo n‹T>Zo Ho$ bE 15 _ZQ >H$m g_` X`m J`m h¡ & àíZ-nÌ H$m dVaU nydm©•

_| 10.15 ~Oo H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg AdY Ho$ Xm¡amZ do CÎma-nwpñVH$m na H$moB© CÎma Zht bI|Jo &

Please check that this question paper contains 15 printed pages.

Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

Please check that this question paper contains 30 questions.

Please write down the Serial Number of the question before

attempting it.

15 minutes time has been allotted to read this question paper. The question

paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the

students will read the question paper only and will not write any answer on

the answer-book during this period.

Page 263: Chemistry Past Papers

56/1 2

gm_mÝ` ZXe :

(i) g^r àíZ AZdm`© h¢ &

(ii) àíZ-g§»`m 1 go 8 VH$ AV bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 1 A§H$ h¡ &

(iii) àíZ-g§»`m 9 go 18 VH$ bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 2 A§H$ h¡§ &

(iv) àíZ-g§»`m 19 go 27 VH$ ^r bKw-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 3 A§H$ h¢ &

(v) àíZ-g§»`m 28 go 30 VH$ XrK©-CÎmar` àíZ h¢ & àË`oH$ àíZ Ho$ bE 5 A§H$ h¢ &

(vi) Amdí`H$VmZwgma bm°J Q>o~bm| H$m à`moJ H$a| & H¡$ëHw$boQ>am| Ho$ Cn`moJ H$s AZw_V Zht h¡ &

General Instructions :

(i) All questions are compulsory.

(ii) Questions number 1 to 8 are very short-answer questions and carry

1 mark each.

(iii) Questions number 9 to 18 are short-answer questions and carry 2 marks

each.

(iv) Questions number 19 to 27 are also short-answer questions and carry

3 marks each.

(v) Questions number 28 to 30 are long-answer questions and carry 5 marks

each.

(vi) Use Log Tables, if necessary. Use of calculators is not allowed.

1. amgm`ZH$ emofU (chemisorption) na VmnH«$_ H$m Š`m à^md hmoVm h¡ ? 1

What is the effect of temperature on chemisorption ?

2. gëda Ho$ ZîH$f©U _| µOÝH$ YmVw H$m Š`m H$m`© hmoVm h¡ ? 1

What is the role of zinc metal in the extraction of silver ?

3. H3PO3 H$s jmaH$Vm (~ogH$Vm) H$VZr hmoVr h¡ ? 1

What is the basicity of H3PO3 ?

Page 264: Chemistry Past Papers

56/1 3 P.T.O.

4. ZåZ Omo‹S>o _| H$aob AUw H$mo nhMmZE : 1

Identify the chiral molecule in the following pair :

5. ZåZ _| go H$m¡Z-gm àmH¥$VH$ ~hþbH$ h¡ ? 1

~yZm-S, àmoQ>rZ|, PVC

Which of the following is a natural polymer ?

Buna-S, Proteins, PVC

6. àmW_H$ Eoamo_¡Q>H$ Eo_rZm| Ho$ S>mBEµOmoZ`_ bdUm| _| n[adV©Z H$mo H$g Zm_ go OmZm OmVm

h¡ ? 1 The conversion of primary aromatic amines into diazonium salts is

known as ___________ .

7. ñ yH«$mog Ho$ Ob-AnKQ>Z (hydrolysis) Ho$ CËnmX Š`m h¢ ? 1

What are the products of hydrolysis of sucrose ?

8. p-_oWb~¡ÝµO¡pëS>hmBS> H$s g§aMZm bIE & 1

Write the structure of p-methylbenzaldehyde.

9. KZËd 2.8 g cm–3 H$m EH$ VÎd \$bH$ Ho$pÝÐV KZmH$ma (f.c.c.) àH$ma H$m _mÌH$ gob ~ZmVm h¡ OgHo$ H$Zmao H$s bå~mB© 4 10–8 cm h¡ & Bg VÎd H$m _moba Ðì`_mZ n[aH$bV H$sOE & 2

(X`m J`m h¡ : NA = 6.022 1023 _mob–1)

An element with density 2.8 g cm–3 forms a f.c.c. unit cell with edge

length 4 10–8 cm. Calculate the molar mass of the element.

(Given : NA = 6.022 1023 mol–1)

Page 265: Chemistry Past Papers

56/1 4

10. (i) LiCl Ho$ Jwbm~r a§J Ho$ bE BgH$m H$g àH$ma H$m A-agg_rH$aU_Vr` (non-stoichiometric) Xmof CÎmaXm`r hmoVm h¡ ?

(ii) NaCl H$g àH$ma H$m agg_rH$aU_Vr` Xmof XImVm h¡ ? 2

AWdm

ZåZbIV nXm| Ho$ Omo‹S>m| Ho$ ~rM Amn d^oXZ H¡$go H$a|Jo : 2

(i) Q>oQ´>mhoS´>b VWm Am°ŠQ>mhoS´>b [aº$`m±

(ii) H«$ñQ>b OmbH$ VWm _mÌH$ gob

(i) What type of non-stoichiometric point defect is responsible for the

pink colour of LiCl ?

(ii) What type of stoichiometric defect is shown by NaCl ?

OR

How will you distinguish between the following pairs of terms :

(i) Tetrahedral and octahedral voids

(ii) Crystal lattice and unit cell

11. Am`Zm| Ho$ ñdVÝÌ nbm`Z gå~ÝYr H$mobamD$e (Kohlrausch) Z`_ bIE & VZwH$aU na db`Z H$s MmbH$Vm H$_ Š`m| hmo OmVr h¡ ? 2

State Kohlrausch law of independent migration of ions. Why does the

conductivity of a solution decrease with dilution ?

12. EH$ amgm`ZH$ A^H«$`m, R P Ho$ bE, g_` (t) Ho$ àV gmÝÐVm (R) _| n[adV©Z H$mo Bg J«m\$ _| XIm`m J`m h¡ & 2

(i) Bg A^H«$`m H$s H$moQ> (order) gwPmBE &

(ii) dH«$ H$s àdUVm (T>bmZ) Š`m hmoJr ?

Page 266: Chemistry Past Papers

56/1 5 P.T.O.

For a chemical reaction R P, the variation in the concentration (R) vs.

time (t) plot is given as

(i) Predict the order of the reaction.

(ii) What is the slope of the curve ?

13. YmVwAm| Ho$ dÚwV²-AnKQ>Zr n[aîH$aU H$m AmYma_yb gÕmÝV g_PmBE & BgH$m EH$ CXmhaU XrOE & 2 Explain the principle of the method of electrolytic refining of metals. Give

one example.

14. ZåZ g_rH$aUm| H$mo nyam H$sOE : 2

(i) P4 + H2O

(ii) XeF4 + O2F2

Complete the following equations :

(i) P4 + H2O

(ii) XeF4 + O2F2

15. ZåZ H$s g§aMZmE± ~ZmBE : 2

(i) XeF2

(ii) BrF3

Draw the structures of the following :

(i) XeF2

(ii) BrF3

16. ZåZ A^H«$`mAm| go gå~pÝYV g_rH$aU bIE : 2

(i) amB_a – Q>r_Z A^H«$`m (ii) db`_gZ g§íbofU (synthesis) Write the equations involved in the following reactions :

(i) Reimer – Tiemann reaction

(ii) Williamson synthesis

Page 267: Chemistry Past Papers

56/1 6

17. ZåZ A^H«$`m H$s H«$`mdY bIE : 2

CH3CH2OH HBr

CH3CH2Br + H2O

Write the mechanism of the following reaction :

CH3CH2OH HBr

CH3CH2Br + H2O

18. ZåZ ~hþbH$m| H$mo àmá H$aZo Ho$ bE à wº$ EH$bH$m| Ho$ Zm_ bIE : 2

(i) ~oHo$bmBQ>

(ii) ZAmoàrZ

Write the name of monomers used for getting the following polymers :

(i) Bakelite

(ii) Neoprene

19. (a) A^H«$`m

Mg (s) + Cu2+ (Obr`) Mg2+ (Obr`) + Cu (s)

Ho$ bE rGo n[aH$bV H$sOE &

X`m J`m h¡ : Eo

gob = + 2.71 V, 1 F = 96500 C _mob –1

(b) Anmobmo (Apollo) A§V[aj àmoJ«m_ Ho$ bE dÚwV² eº$ CnbãY H$amZo Ho$ bE

à`wº$ gob Ho$ àH$ma H$m Zm_ bIE & 3

(a) Calculate rGo for the reaction

Mg (s) + Cu2+ (aq) Mg2+ (aq) + Cu (s)

Given : Eocell = + 2.71 V, 1 F = 96500 C mol–1

(b) Name the type of cell which was used in Apollo space programme

for providing electrical power.

Page 268: Chemistry Past Papers

56/1 7 P.T.O.

20. pñWa Am`VZ AdñWm _| SO2Cl2 Ho$ àW_ H$moQ> Ho$ Vmnr` dKQ>Z Ho$ Xm¡amZ ZåZbIV

Am§H$‹S>o àmá hþE :

SO2Cl2 (J¡g) SO2 (J¡g) + Cl2 (J¡g)

à`moJ g_`/s–1 gH$b Xm~/dm`w_ÊS>b

1 0 0.4

2 100 0.7

doJ Z`Vm§H$ n[aH$bV H$sOE & 3

(X`m J`m h¡ : log 4 = 0.6021, log 2 = 0.3010)

The following data were obtained during the first order thermal

decomposition of SO2Cl2 at a constant volume :

SO2Cl2 (g) SO2 (g) + Cl2 (g)

Experiment Time/s–1 Total pressure/atm

1 0 0.4

2 100 0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

21. B_ëeÝg Š`m hmoVo h¢ ? BZHo$ d^Þ àH$ma Š`m h¢ ? àË`oH$ àH$ma H$m EH$$ CXmhaU XrOE & 3

What are emulsions ? What are their different types ? Give one example

of each type.

22. ZåZbIV Ho$ H$maU XrOE : 3

(i) (CH3)3 P = O Vmo nm`m OmVm h¡ naÝVw (CH3)3 N = O Zht _bVm &

(ii) BboŠQ´>m°Z àmá H$aZo H$s G$UmË_H$ M• dmbr EÝW¡ënr H$m _mZ gëµ\$a H$s Anojm

Am°ŠgrOZ Ho$ bE H$_ hmoVm h¡ &

(iii) H3PO3 H$s Anojm H3PO2 AYH$ à~b AnMm`H$ h¡ &

Page 269: Chemistry Past Papers

56/1 8

Give reasons for the following :

(i) (CH3)3 P = O exists but (CH3)3 N = O does not.

(ii) Oxygen has less electron gain enthalpy with negative sign than

sulphur.

(iii) H3PO2 is a stronger reducing agent than H3PO3.

23. (i) g§H$a [Cr(NH3)4 Cl2]Cl H$m IUPAC Zm_ bIE &

(ii) g§H$a [Co(en)3]3+ H$g àH$ma H$s g_md`dVm XImVm h¡ ?

(en = B©WoZ-1,2-S>mBEo_rZ)

(iii) [NiCl4]2– Š`m| AZwMwå~H$s` hmoVm h¡ O~H$ [Ni(CO)4] àVMwå~H$s` hmoVm h¡ ?

(na_mUw H«$_m§H$$ : Cr = 24, Co = 27, Ni = 28) 3

(i) Write the IUPAC name of the complex [Cr(NH3)4 Cl2]Cl.

(ii) What type of isomerism is exhibited by the complex [Co(en)3]3+ ?

(en = ethane-1,2-diamine)

(iii) Why is [NiCl4]2– paramagnetic but [Ni(CO)4] is diamagnetic ?

(At. nos. : Cr = 24, Co = 27, Ni = 28)

24. (a) ZåZ _| go àË`oH$ A^H«$`m Ho$ à_wI EH$h¡bmoOZr CËnmXm| H$s g§aMZmE± ~ZmBE :

(b) ZåZ `w½_m| _| go H$m¡Z-gm h¡bmoOZr `m¡JH$ SN2 A^H«$`m _| AYH$ Vrd«Vm go A^H«$`m H$aoJm :

(i) CH3Br AWdm CH3I

(ii) (CH3)3 C – Cl AWdm CH3 – Cl 3

Page 270: Chemistry Past Papers

56/1 9 P.T.O.

(a) Draw the structures of major monohalo products in each of the

following reactions :

(b) Which halogen compound in each of the following pairs will react

faster in SN2 reaction :

(i) CH3Br or CH3I

(ii) (CH3)3 C – Cl or CH3 – Cl

25. ZåZbIV Ho$ H$maU bIE : 3

(i) V¥Vr`H$ Eo_rZm| (R3N) H$s VwbZm _| àmW_H$ Eo_rZm| (R-NH2) Ho$ ŠdWZm§H$ CƒVa

hmoVo h¢ &

(ii) EoZbrZ \«$sS>ob – H«$mµâQ>²g A^H«$`m Zht XoVr &

(iii) Obr` db`Z _| (CH3)3N H$s VwbZm _| (CH3)2NH AYH$ jmar` hmoVr h¡ &

AWdm

ZåZ A^H«$`mAm| _| A, B Am¡a C H$s g§aMZmE± XrOE : 3

(i) C6H5NO2 HClSn

A K273

HClNaNO2

B

OH2 C

(ii) CH3CN

H/OH2

A 3NH

B KOHBr2

C

Account for the following :

(i) Primary amines (R-NH2) have higher boiling point than tertiary

amines (R3N).

(ii) Aniline does not undergo Friedel – Crafts reaction.

(iii) (CH3)2NH is more basic than (CH3)3N in an aqueous solution.

OR

Page 271: Chemistry Past Papers

56/1 10

Give the structures of A, B and C in the following reactions :

(i) C6H5NO2 HClSn

A K273

HClNaNO2

B

OH2 C

(ii) CH3CN

H/OH2

A 3NH

B KOHBr2

C

26. àmoQ>rZm| go gå~pÝYV ZåZ nXm| H$s n[a^mfmE± XrOE : 3

(i) noßQ>mBS> Am~ÝY

(ii) àmW_H$ g§aMZm

(iii) dH¥$VrH$aU

Define the following terms as related to proteins :

(i) Peptide linkage

(ii) Primary structure

(iii) Denaturation

27. díd ñdmñÏ` Xdg Ho$ Adga na, S>m°. gVnmb Zo nmg Ho$ Jm±d _| ahZo dmbo YZhrZ

H$gmZm| Ho$ bE EH$ ‘ñdmñÏ` H¡$ån’ bJm`m & Om±M Ho$ ~mX, Cgo `h XoI H$a YŠH$m bJm

H$ ~ma-~ma H$sQ>ZmeH$m| Ho$ gånH©$ _| AmZo Ho$ H$maU H$gmZm| _| go AYH$m| H$mo H¡$Ýga H$m

amoJ hmo J`m Wm & CZ_| go ~hþVm| H$mo _Yw_oh ^r Wm & CÝhm|Zo CZ_| YZ_wº$ Am¡fY`m± ~m±Q>t &

S>m°. gVnmb Zo Bg ~mV H$s gyMZm VËH$mb ZoeZb øy_Z amBQ²>g H$_eZ (NHRC) H$mo

Xr & NHRC Ho$ gwPmdm| na gaH$ma Zo ZU ©` b`m H$s S>m°ŠQ>ar ghm`Vm Am¡a dÎmr`

ghm`Vm bmoJm| H$mo Xr OmE Am¡a ^maV Ho$ g^r Jm±dm| _| KmVH$ amoJm| Ho$ à^md H$mo amoH$Zo Ho$

bE AË`YH$ gwdYm dmbo AñnVmb Imobo OmE± &

(i) (a) S>m°. gVnmb Am¡a (b) NHRC Ûmam Xem©B© JB© _mÝ` ~mV| bIE &

(ii) ApÝV_ H¡$Ýga _| nr‹S>m go ~MmZo Ho$ bE _w»`V`m H$m¡Z-gr nr‹S>mZmeH$ Am¡fY`m±

à`wº$ H$s OmVr h¢ ?

(iii) _Yw_oh Ho$ amoJ`m| Ho$ bE gwPmE JE H¥$Ì_ _YwH$mam| _| go H$gr EH$ H$m CXmhaU

XrOE & 3

Page 272: Chemistry Past Papers

56/1 11 P.T.O.

On the occasion of World Health Day, Dr. Satpal organized a ‘health camp’

for the poor farmers living in a nearby village. After check-up, he was

shocked to see that most of the farmers suffered from cancer due to regular

exposure to pesticides and many were diabetic. They distributed free

medicines to them. Dr. Satpal immediately reported the matter to the

National Human Rights Commission (NHRC). On the suggestions of

NHRC, the government decided to provide medical care, financial

assistance, setting up of super-speciality hospitals for treatment and

prevention of the deadly disease in the affected villages all over India.

(i) Write the values shown by

(a) Dr. Satpal

(b) NHRC.

(ii) What type of analgesics are chiefly used for the relief of pains of

terminal cancer ?

(iii) Give an example of artificial sweetener that could have been

recommended to diabetic patients.

28. (a) ZåZ nXm| H$s n[a^mfm XrOE :

(i) _mobaVm

(ii) _mobb CÞ`Z pñWam§H$ (Kb)

(b) EH$ Obr` db`Z _| àV bQ>a db`Z _| 15 g `y[a`m (_moba Ðì`_mZ =

60 g _mob–1) KwbV h¡ & Bg db`Z H$m namgaU Xm~ Ob _| ½byH$moµO (_moba

Ðì`_mZ = 180 g _mob–1) Ho$ EH$ db`Z Ho$ g_mZ (g_namgar) h¡ & EH$ bQ>a

db`Z _| CnpñWV ½byH$moµO H$m Ðì`_mZ n[aH$bV H$sOE & 2, 3

AWdm

Page 273: Chemistry Past Papers

56/1 12

(a) EWoZm°b Am¡a EogrQ>moZ H$m _lU H$g àH$ma H$m dMbZ XImVm h¡ ? H$maU

XrOE &

(b) Ob _| ½byH$moµO (_moba Ðì`_mZ = 180 g _mob–1) Ho$ EH$ db`Z na bo~b bJm

h¡, 10% (Ðì`_mZ AZwgma) & Bg db`Z H$s _mobbVm Am¡a _mobaVm Š`m hm|Jo ?

(db`Z H$m KZËd = 1.2 g mL–1) 2, 3

(a) Define the following terms :

(i) Molarity

(ii) Molal elevation constant (Kb)

(b) A solution containing 15 g urea (molar mass = 60 g mol–1) per litre

of solution in water has the same osmotic pressure (isotonic) as a

solution of glucose (molar mass = 180 g mol–1) in water. Calculate

the mass of glucose present in one litre of its solution.

OR

(a) What type of deviation is shown by a mixture of ethanol and

acetone ? Give reason.

(b) A solution of glucose (molar mass = 180 g mol–1) in water is

labelled as 10% (by mass). What would be the molality and

molarity of the solution ?

(Density of solution = 1.2 g mL–1)

29. (a) ZåZ g_rH$aUm| H$mo nyam H$sOE :

(i) Cr2O72– + 2OH

(ii) MnO4– + 4H+ + 3e–

Page 274: Chemistry Past Papers

56/1 13 P.T.O.

(b) ZåZ Ho$ H$maU bIE :

(i) Zn H$mo g§H«$_U VÎd Zht _mZm OmVm &

(ii) g§H«$_U YmVw ~hþV go g§H$a ~ZmVo h¢ &

(iii) Mn3+/Mn2+ `w½_, Cr3+/Cr2+ `w½_ go H$ht AYH$ Eo _mZ aIVm h¡ & 2, 3

AWdm

(i) g§aMZm n[adV©ZerbVm Am¡a amgm`ZH$ A^H«$`merbVm Ho$ g§X^© _| b¡ÝWoZm°BS>m|

Am¡a EopŠQ>Zm°`S>m| Ho$ ~rM ^oX bIE &

(ii) b¡ÝWoZm°BS> ûm¥§Ibm Ho$ Cg gXñ` H$m Zm_ bIE, Omo +4 Am°ŠgrH$aU AdñWm

XImZo Ho$ bE àgÕ h¡ &

(iii) ZåZ g_rH$aU H$mo nyam H$sOE : MnO4

– + 8H+ + 5e–

(iv) Mn3+ Am¡a Cr3+ _| go H$m¡Z AYH$ AZwMwå~H$s` h¡ Am¡a Š`m| ?

(na_mUw H«$_m§H$ : Mn = 25, Cr = 24) 5

(a) Complete the following equations :

(i) Cr2O72– + 2OH

(ii) MnO4– + 4H+ + 3e–

(b) Account for the following :

(i) Zn is not considered as a transition element.

(ii) Transition metals form a large number of complexes.

(iii) The Eo value for the Mn3+/Mn2+ couple is much more positive

than that for Cr3+/Cr2+ couple.

OR

Page 275: Chemistry Past Papers

56/1 14

(i) With reference to structural variability and chemical reactivity,

write the differences between lanthanoids and actinoids.

(ii) Name a member of the lanthanoid series which is well known to

exhibit +4 oxidation state.

(iii) Complete the following equation :

MnO4– + 8H+ + 5e–

(iv) Out of Mn3+ and Cr3+, which is more paramagnetic and why ?

(Atomic nos. : Mn = 25, Cr = 24)

30. (a) ZåZ A^H$maH$m| go CH3CHO H$s A^H«$`m H$aZo na ~Zo CËnmXm| H$mo bIE :

(i) HCN

(ii) H2N – OH

(iii) VZw NaOH H$s CnpñWV _| CH3CHO

(b) ZåZ `m¡JH$ `w½_m| _| AÝVa XImZo Ho$ bE gab amgm`ZH$ narjU bIE :

(i) ~¡ÝµOmoBH$ Aåb Am¡a µ\$sZm°b

(ii) àmonoZb Am¡a àmonoZmoZ 3, 2

AWdm

(a) ZåZ Ho$ H$maU bIE :

(i) CH3COOH H$s VwbZm _| Cl – CH2COOH AYH$ à~b Aåb h¡ &

(ii) H$m~mpŠgbH$ Aåb H$m~mZb g_yh H$s A^H«$`mE± Zht XoVo &

(b) ZåZ Zm_ Ym[aV A^H«$`mAm| Ho$ bE amgm`ZH$ g_rH$aU bIE :

(i) amoµOoZ_wÝS> AnM`Z

(ii) H¡$ZµOmamo A^H«$`m

(c) CH3CH2 – CO – CH2 – CH3 Am¡a CH3CH2 – CH2 – CO – CH3 _| go

H$m¡Z Am`moS>moµ\$m°_© narjU XoVm h¡ ? 2, 2, 1

Page 276: Chemistry Past Papers

56/1 15 P.T.O.

(a) Write the products formed when CH3CHO reacts with the

following reagents :

(i) HCN

(ii) H2N – OH

(iii) CH3CHO in the presence of dilute NaOH

(b) Give simple chemical tests to distinguish between the following

pairs of compounds :

(i) Benzoic acid and Phenol

(ii) Propanal and Propanone

OR

(a) Account for the following :

(i) Cl – CH2COOH is a stronger acid than CH3COOH.

(ii) Carboxylic acids do not give reactions of carbonyl group.

(b) Write the chemical equations to illustrate the following name

reactions :

(i) Rosenmund reduction

(ii) Cannizzaro’s reaction

(c) Out of CH3CH2 – CO – CH2 – CH3 and CH3CH2 – CH2 – CO – CH3,

which gives iodoform test ?

Page 277: Chemistry Past Papers

1

Marking Scheme Chemistry - 2014

Outside Delhi- SET (56 /1) 1 It first increases then decreases or graphical representation. 1

2 Zn acts as reducing agent. 1

3 2 1

4

2–Chlorobutane or or first molecule of the pair.

1

5 Proteins 1

6. Diazotization 1

7. Glucose & Fructose 1

8.

1

9. Given; d = 2.8g/cm3 ; Z = 4 ; a = 4 x 10–8 cm NA = 6.022 x 1023 per mol

d =

or M =

⟹ M = 2.8gcm-34x10-8cm

3x6.022x1023

4

M = 2.8 x 16 x 10–1 x 6.022 = 26.97 g/mol

½

½

1

10 (i) Metal excess defect / Metal excess defect due to anionic vacancies filled by free electrons

/ Due to F – centers.

(ii) Schottky defect.

1

1

Or

Page 278: Chemistry Past Papers

2

10 (i) Tetrahedral void is surrounded by 4 constituent particles (atoms / molecules / ions).

Octahedral void is surrounded by 6 constituent particles (atoms / molecules / ions).

OR

radius ratio (r + /r -) for Tetrahedral void is 0.225 & radius ratio for octahedral voids is

0.414

(ii) A regular three dimensional arrangement of points in space is called a crystal lattice.

Unit cell is the smallest portion of a crystal lattice which, when repeated in three

directions, generates an entire lattice. / unit cell is the miniature of crystal lattice /

microscopic edition of the crystal lattice.

1

1

11 Kohlrausch law of independent migration of ions. The law states that limiting molar

conductivity of an electrolyte can be stated as the sum of the individual contributions of the

anion and cation of the electrolyte.

On dilution,the conductivity (κ) of the electrolyte decreases as the number of ions per unit

volume of solution decreases.

1

1

12 (i) Zero order reaction

(ii) slope = -k

1

1

13 In this method, the impure metal is made to act as anode. A strip of the same metal in pure

form is used as cathode. They are put in a suitable electrolytic bath containing soluble salt of

the same metal. Pure metal is deposited at the cathode and impurities remain in the solution.

For example: electro refining of Cu, Ag, Au (any one)

1

1

14 (i) P4 + H2O no reaction or if attempted in any form, award one mark

(ii) XeF4 + O2F2 XeF6 + O2.

1

1

15

1+1

16 Reimer-Tiemann reaction

1

Page 279: Chemistry Past Papers

3

Williamson synthesis

1

17 HBr → H+ + Br-

Or

( where R = -CH3)

½

½

1

18 (i) Phenol & Formaldehyde

(ii) 2–Chloro–1,3–butadiene (or Chloroprene)

1

1

19 (a) Given EoCell = +2.71V & F = 96500C mol-1 n = 2 (from the given reaction)

∆rGO = – n x F x EoCell

∆rGO = – 2 x 96500 C mol-1 x 2.71V

= - 523030 J / mol or - 523.030 kJ / mol

(b) Hydrogen – oxygen fuel Cell / Fuel cell.

½

½

1

1

20 SO2 Cl2 → SO2 + Cl2

At t = 0s 0.4 atm 0 atm 0 atm

At t = 100s (0.4 – x) atm x atm x atm

Pt = 0.4 – x + x + x

Pt = 0.4 + x

0.7 = 0.4 + x

x = 0.3

k = 2.303

t log

"#

$"#%"&

1

Page 280: Chemistry Past Papers

4

k = 2.303

t log

0.4

0.8-0.7

k = 2.303

100s log

0.4

0.1

k = $.)*)

+**, x 0.6021 = 1.39 x 10-2 s-1

1

1

21 These are liquid-liquid colloidal systems or the dispersion of one liquid in another liquid.

Types: (i) Oil dispersed in water (O/W type) Example; milk and vanishing cream

(ii) Water dispersed in oil (W/O type) Example; butter and cream.

(Any one example of each type)

1

½ +½

½ +½

22 (i) As N can’t form 5 covalent bonds / its maximum covalency is four.

(ii) This is due to very small size of Oxygen atom / repulsion between electrons is large in

relatively small 2p sub-shell.

(iii) In H3PO2 there are 2 P–H bonds, whereas in H3PO3 there is 1 P–H bond

1

1

1

23 (i) Tetraamminedichloridochromium (III) chloride.

(ii) Optical isomerism

(iii) In [NiCl 4]2– ; Cl– acts as weak ligand therefore does not cause forced pairing, thus

electrons will remain unpaired hence paramagnetic.

In [Ni(CO)4] ; CO acts as strong ligand therefore causes forced pairing, thus electrons will

become paired hence diamagnetic.

1

1

½ +

½

24 (a)

(b) (i) CH3–I

(ii) CH3–Cl

1

1

½ +½

25

(i) As primary amines form inter molecular H – bonds, but tertiary amines don’t form H –

bonds.

(ii) Aniline forms salt with Lewis acid AlCl3.

(iii) This is because of the combined effect of hydration and inductive effect (+I effect).

1

1

1

Page 281: Chemistry Past Papers

5

Or

25 (i) C6H5NO2-./012 C6H5NH2

34/012;$6)7 C6H5N2+Cl–

043 C6H5OH

A B C

(ii) CH3CN 043/09 CH3COOH

0∆

CH3CONH2 :;4/730 CH3NH2

A B C

½+½

½+½

26 (i) Peptide linkage is an amide formed between –COOH group and –NH2 group ( -CO-NH- )

(ii) Specific sequence of amino acids in a polypeptide chain is said to be the primary

structure of the protein.

(iii) When a protein in its native form, is subjected to change in temperature or change in pH,

protein loses its biological activity. This is called denaturation of protein

1

1

1

27 (i) (a) dedicated towards work/ kind/ compassionate (any two).

(b) Dutiful / caring / humane in the large interest of public health in rural area.

(any other suitable value)

(ii) Narcotic analgesics

(iii) Aspartame / Saccharin / Alitame / Sucrolose.(any one)

1

½

½

1

28

(a)

(i) Molarity is defined as number of moles of solute dissolved in one litre of solution.

(ii) It is equal to elevation in boiling point of 1 molal solution.

(b) For isotonic solutions: π urea = π glucose

<=>?@

=>?@AB =

<CD=EFB?CD=EFB?AB

(As volume of solution is same)

<=>?@=>?@

= <CD=EFB?CD=EFB?

or +GH

I*JKL2MN = <CD=EFB?

+O*JKL2MN

W Glucose = +GJ+O*JKL2MN

I*JKL2MN = 45g

1

1

½

½

1

1

OR

28 (a) It shows positive deviation.

It is due to weaker interaction between acetone and ethanol than ethanol-ethanol interactions.

1

1

Page 282: Chemistry Past Papers

6

(b) Given: WB = 10g WS = 100g, WA = 90g MB = 180g/mol & d = 1.2g/m L

M=<Q%S.TUQV+*L2.WQ.

M=+*+.$+*

+O* = 0.66 M or 0.66 mol/L

m=<X+***

X<(U.J)

m=+*+***

+O*[*

= 0.61m or 0.61mol/kg (or any other suitable method)

½

1

½

1

29

(a) (i) Cr2O72– + 2 OH–

2CrO4

2– + H2O

(ii) MnO4– + 4H+ + 3e–

MnO2 + 2H2O

(b) (i) Zn / Zn2+ has fully filled d orbitals.

(ii) This is due to smaller ionic sizes / higher ionic charge and availability of d orbitals.

(iii) because Mn +2 is more stable(3d5) than Mn3+ (3d4). Cr+3 is more stable due to t2g3 / d3

configuration.

1

1

1

1

1

Or

29 (i)

Lanthanoids Actinoids

Atomic / ionic radii does not show much

variation / +3 is the most common oxidation

state, in few cases +2 & +4

Atomic / ionic radii show much variation /

Besides +3 oxidation state they exibit

+4,+5,+6,+7 also.

They are quite reactive Highly reactive in finely divided state

(Any two Points)

(ii) Cerium (Ce4+)

(iii) MnO4– + 8H+ + 5e–

Mn2+ + 4H2O

(iv) Mn3+ is more paramgnetic

Because Mn3+ has 4 unpaired electrons (3d4) therefore more paramagnetic whereas Cr3+ has 3

1

1

1

1

½

½

Page 283: Chemistry Past Papers

7

unpaired electrons (3d3).

30

(a) (i)

(ii) CH3CH=N–OH

(iii)

(b) (i) Add neutral FeCl3 in both the solutions, phenol forms violet colour but benzoic acid

does not.

(ii) Tollen’s reagent test: Add ammoniacal solution of silver nitrate (Tollen’s reagent) in

both the solutions propanal gives silver mirror whereas propanone does not.

(or any other correct test)

1

1

1

1

1

OR

30 (a) (i) As Cl acts as electron withdrawing group ( – I effect) ,CH3 shows +I effect.

(ii) The carbonyl carbon atom in carboxylic acid is resonance stabilised.

(b) (i) Rosenmund reduction:

1

1

Page 284: Chemistry Past Papers

8

Or RCOCl 04/\%:-3] RCHO +HCl.

(ii) Cannizzaro’s Reaction:

Or With bezaldehyde

(c) CH3–CH2–CH2–CO–CH3.

1

1

1

Page 285: Chemistry Past Papers

fi

iirTi.Roll No.

Series : OSR/I *]*,. s6nn,ffir-9fiffir *e,

qqEwirffi r

Candidates must write the Code onthe title page of the answer-book.

o ![ttqt dq ffi d fu'eq sq-rl:t $qfr gsa 11 t r

o lrFr-rrir ErF+ rrq +t eilt fqqrrq*ts;rrqr *l ur* rtrcgfir+t *e-gua.n ffi r

o grrfi qiq *t d f+'Vq nFT-rEr SO lrrq t r

r StrrfilrFtmvrrfrsqrvS66T++qtrd, svtclmqia^ wflqftrd I

o gt wT-rH st q6+ + fdq 15 tne EFI TFrq flqqrrqr er fuarur Wlq ii to.ts qiflq,,qr !ilr+'n r 10.15 Tq t 10.30 ql a*"or* *m qsT-wr qtn et' qs erqftr + qkH t s+r-yfiffirwettrirqaTfndi r

o Please check that this question paper contains 11 printed pages.

r Code number given on the right hand side of the question paper should be written on thetitle page of the answer-book by the candidate.

o Please check that this question paper contains 30 questions.

o Please write down the Serial Number of the question before attempting it.o 15 minutes time has been allotted to read this question paper. The question paper will be

disfibuted at 10.15 a.m. From 10.15 a.m. to 10.30 a.m,, the students will only read thequestion paper and will not write any answer on the answer-book during this period.

Tqrq;Tfrm@OCHEMISTRY (Theory)

fuiffuerrt : 3 qv*j yafuw etq :70Timeallowed:3hours I t MaximumMarks:7O

snrr<r+qYr.

(i) wtlsw efqqzii r

(ii) vw-d@rl da aaerfr ag-rafuvwt tv-dqsw #ftryr ;ra& r

(iii) wld@rg *ra aoag-sadqsw* rsa*€frw*fu2 erqr* I

(iv) sw-iqrlg tzr aqq1ag-mt+r'w t rv-dqvw #frrq's eiqt r

(v) sw-(i@rza *ro qlt-rmfrqvwt rs'dqs?a#ftzq's tiqt r

(vi) qrqwffiqstrdfuTfuitwyqfu *1 7 ffeyda<i *vqlrql aryqfu aaf* I

lP.T.O.

Page 286: Chemistry Past Papers

General Instructions :

(i) All questions are compulsory.

(ii) Question numbers I to I are very short-answer questions and carry I mark each.

(iii) Question numbers 9 to 18 are short-answer questions and carry 2 marks each.

(iv) Question numbers 19 to 27 are also short-answer questions and carry i marks

each.

(v) Question numbers 28 to 30 are long-answer questions and carry 5 mnrks each.

(vi) Use Log Tables, if necessary. Use of calculators is not allowed.

1.'qfl i[ iH' eik'tm i[ srfr' ]FFR *' qqer+t s'r gs-ttsgqrflur H r

Give one example each of 'oil in water' and 'water in oil' emulsion.

2. foqfaaWns*qiw*sirg.t*irstHfu+Hqiq+ qqq'*,,srnrqrfuqrqmrt? 1

Which reducing agent is employed to get copper from the leached low grade copperore ?

3. frTq ffi t st T €ifrq^eTr+ 6tdr t eilr wif r

[Co(NH3)6]3* oi [co(en)r]3+

Which of the following is more stable complex and why ?

[Co(NH)6]3+ and [Co(en)r]3+

4. rq dFIfi.Hr IUPAC -IT ImK+ :

cHr-cH-cHr-COOHI

OHWrite the IUPAC name of the compound.

cHr-cH-cHr-COOHI

OH

5. Eq oTrq€tqti 6*rn-emuHiy + t st rn qftrm'qruvflE t rs-qrdtr'ffi efu p-qrirftrilH

Which of the following isomers is more volatile :

o-nitrophenol or p-nitrophenol ?

6. vrrwrur$ (€HrEqi-dtfir) kmr xr di t' rWhat are isotonic solutions ?

56tUt

Page 287: Chemistry Past Papers

7. fiffi dffi q+ qr+ Tr* goqvfr-dnr *'mc d q-cftqa 61m :

C6H5NH2, (c2Hr2NH eftr crHrNtt,

Arrange the following compounds in increasing order of solubility in water :

c6HsNH2, (C2H,2NH, C2H5NH2

8. €d +qi st'il ii + frt qI EreT ii ffi tor t tWhich of the two components of starch is water soluble ?

9. ll.2 gcm-3 qT€ etr + x 10 cm ffi #t ff or qir.Htf f.c.c. afl?rcr rqrf,r t I € HErqrqrqruJu'qqrrmqfimitrdqfrH t 2

(Na = 6'022 x 1023 fr6-t;

An element with density tl.2 gcm-3 forms a f.c.c. lattice with edge length of 4 x 10-8 cm.

Calculate the atomic mass of the element.

(Given : No = 6.022x 1023 mol-l)

10. qfi M rr q+*qr €Fapi tx-w) q,r flTfrqq H' sTri & q+ eq+f *ffi ffi : 2

A+ B- A+ B- A+

B-OB-A+B-A+B-A+0A+B- A+ B- A+ B_

(i) Es fu€m Enr + HT qH Brer*. GmaArft*o dq tqqqT qrer t r(ii) Es iq *'qnor P*,w *'qqo tr fu€ Fnr wfltt qgdl t ?

(ii1 fus r+n*'silqk*.qEr tfir qiq Pqqr+ t tExamine the given defective crystal

A+ B- A+ B- A+

B-OB-A+B_A+B-A+0A+B- A+ B- A+ B-

Answer the following questions :

(i) What type of stoichiometric defect is shown by the crystal ?

(ii) How is the density of the crystal affected by this defect ?

(iii) What type of ionic substances show such defect ?

$fltfi 3 IP.T.O.

Page 288: Chemistry Past Papers

n. qMmfr ftiH fu' oir"re rqqn = 256 g dtrr +'q\Fffi ft1 fuir+ rTHr 6t 75 g ffi qifir En+ fu'Es*-f6qi-qrrf o.+s K *t EF+ E+ qrA' r (r! = s.tzKkg futr. 2

Calculate the mass of compound (molar mass = 256 gmol-l) to be dissolved in 75 gofbenzene to lower its freezing point by 0.48 K (& = 5.tZ K kg mol-l).

t2. qra ernlt fldq q+ qftqr$ sils*l*tttrofuqtsdr fttrd r

Define an ideal solution and write one of its characteristics.

I 3. aflItrqr *' *q (order) ett Er*t srTurErfi (molecularity) + s't q Qr.ffi ftfui t 2

Write two differences between 'order of reaction' and 'molecularity of reaction'.

14. urEeif *.yilqr *t FTrr frfriqi *. e+nrcfc frqq flfifis+ '

(i) =f*

(*) qftFhn frfrT

(i0 altffifrftiOutline the principles behind the refining of metals by the following methods :

(i) Zone refining method

(ii) Chromatographicmethod

15. ga q-ssfipnr+dr"if e Trr *t :

(i) CarPr+ HrO ->(ii) Cu + HrSOoutO ->

g[?rdlT

fiTE q\trs q*it qi y+*- qrq ffi '1w eripn anafuro E1k+ :

(i) HF, HC/, Hsr drHI - EEfr g* err**r M-s tdet wsr(ii) H2O, H2S, HrSe dturTe -v6* g$ enm HqHr srEqr

Complete the following chemical equations :

(i) C\Pz+ HrO -+

(i0 Cu + HrSOo(conc.) -+

ORArrange the following in the order of property indicated against each set :

(i) HF, HCr, HBr, HI - increasing bond dissociation enthalpy.

(ii) H2O, H2S, HrSe, HrTe - increasing acidic character.

16. ri+"r 1cr(xg 3)4ct2i+ sT rupAC qrq fud r 16 flsq mnr +t rmtErqErff (isomerism) ftrcrdr

ttWrite the IUPAC name of the complex [Cr(NH)aCl21+. What type of isomerism does

it exhibit ?

Page 289: Chemistry Past Papers

L7 . (i) fua gr t qir qr tka i-iflststiT t Gil erRr*.+ s*z orF+fuur tar t z z

nn(a)

Br a;

(ii) Frrr ftxftrqt s*t *r s*z t qt rft Brfth.qr at fr t(a) kqrg Et wrerlT (inversion)

(b) iftr+fiwr(Racemisation)(i) Which alkyl halide from the following pair is chiral and undergoes faster S*2

reaction ?nA \nBrlBr

(a) (b)

(ii) Out of S*1 and S*2, which reaction occurs with

(a) Inversionofconfiguration(b) Racemisation

18. frq t ur+o srfihqr if xgq qtritd 31q1q6t ifir M :

(i) o_ou so%,

(ii) O-cHz-cH:cH'+1*' ffi'

Draw the structure of major monohalo product in each of the following reactions :

(i) O-ou s9c4

'(ii) GcHz - CH: CH2 + HBr Peroxide'

19. (a) steisfur erftNilqur €rdrfr *. ffi ulq qruT q Nt + qftNilsrur + fu+ qqio.ur

fed r

(b) ffitrk+.ria +t r'* teiqffi kri r

(c) r+1Fr-d srcrsTr + m."it *^ snqn q dkd (associated) qEt-ifl?rs ek W+rrTq +fl?rginq6-qs'Bqrflsrffi r 3

(a) In reference to Freundlich adsorption isotherm write the expression foradsorption of gases on solids in the form of an equation.

O) Write an important characteristic of lyophilic sols.

(c) Based on type of particles of dispersed phase, give one example each ofassociated colloid and multimolecular colloid.

S6lUt s tp.T.O.

Page 290: Chemistry Past Papers

20. (a) frq qq.Sf st d'r*rdt tfisn qfrH :

(i) XeOFo

(i0 H2so4

(b) Y+fr srcsts ak mm srstq + 'ffnffi ,tE s'r rqa nfrH r

(a) Draw the structures of the following molecules :

(i) XeOFo

(ii) H2so4

(b) Write the structural difference between white phosphorus and red phosphorus.

2t. flqr+'ERor frfiri :

(0 PC/3 st er*n eCl, qftm-stiiqW (covalent) t I

(ii) HC/ t erFhqT *i .R elt t Feclrqf,r t Fec/, roT r

(iii) e*ilq wl it i o-o *sarqrEqr qq1a fi et-fr t I

Account for the following :

(i) PC/, is more covalent than PC/r.

(ii) Iron on reaction with HC/ forms FeClrand not FeC/r.

(iii) The two O-O bond lengths in the ozone molecule are equal.

22. fury qs6 srqqr ii sorcl, *'qqq mq *'ar*q fuesOrC/r(e)---+ SO2(g) + C/2(B)

itFrrr gfi5 ,Iqt 6g :

rqTTT IITrt/s-1 Ftraqrqrdqrilrgfr1

20

r000.40.7

+rflFniq,,qfi$ftrd+tH r

(1og 4 = 0.6021, log 2 = 0.3010)

The following data were obtained during the frst order thermal decomposition ofSO2C/2 at a constant volume :

SOrC/r(S) ---+ SO2( 91 + Cl2G)

Experiment Time/s-1 Total pressure/atm

1

2

0

100

0.4

0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)6

3

3

3

Page 291: Chemistry Past Papers

23. (i) edqq Hqq +H gi En+ qrd Tfi-qdi eB q"frib *'qi sqrcrur H r

(ii) fftRhfrwrdlt rqs tstrcrqH r

(iii) Wq (asparrame) mr sq+q Fil Arrd dGsFii ortr$Efui tro'rftflqm t r 3

(i) Give two examples of macromolecules that are chosen as drug targets.

(ii) What are antiseptics ? Give an example.

(iii) Why is use of aspartame limited to cold foods and soft drinks ?

24. (i) F*q frErirr *t +.+ t rm qT sienq (night-blindness) ei qrar t t(ii) sT qTr isr qrq frrt qi +f, ptta ;gMcrs tt fre-or t r

(iii) HI t sfiPrqr ERr <T+tq n-t*ilq q?n t I q6 flsqr r6ts *t rfir qry*1 il wrqintrt ? 3

(i) Deficiency of which vitamin causes night-blindness ?

(ii) Name the base that is found in nucleotide of RNA only.

(iii) Glucose on reaction with HI gives n-hexane. What does it suggest about thestructure of glucose ?

25. raTrftar + &ii w +s'Hrr qr+ *'sqrfr, \rs'q'd + BTrt + T6 fiTUiq fuqr t*,'q6 ialril siqkflERuT eil q$r tfr qr

"FTrfisr + ftif + gqtTlq t qtd qtt r Eu rSqqr q+ erftrs. ulTI*ffir+ + fu+ sdl'+ ESt q.€if *'qrq flqffir +d H oilr Edli qM H qdt, eqq

5-sr-rqTtf etk Miza fit $rrs + qA dt r qct urit + yur tsqr fu q5r r* ftigtkotrs++Hq6teTrfir*.+q?if q,rfult-rfi r 3

Btrttfi iHrs,, *1 qr+-r fiTq wqi * srr t :

(0 orii rro wr rt€ Erdrq rri ?

(ii) ffi g?rqr NFftqg Hr d+ S r q+*rtroe+etur t r

(iii) wt dd*q wr (condensation) t erqqr im-ir (addition) frfrq tAfter the ban on plastic bags, students of one school decided to make the people aware

of the harmful effects of plastic bags on environment and Yamuna River. To make theawareness more impactful, they organized rally by joining hands with other schools

and distributed paper bags to vegetable vendors, shopkeepers and departmental stores.

All students pledged not to use polythene bags in future to save Yamuna River.' After reading the above passage, answer the following questions :

(i) What values are shown by the students ?

(ii) What are biodegradable polymers ? Give one example.

(iii) Is polythene a condensation or an addition polymer ?

56lut 7 !P.T.O.

Page 292: Chemistry Past Papers

26. (a) frq srftfuqr +t ffdEfu ffi :

cH3cH2oH IrBr , cHrcHrBr + Hro

(b) ltq-&m srfuf*qr+ffisfrq.urfod r

(a) Write the mechanism of the following reaction :

cH3cH2oH HBr , cHrCHrBr + Hro

(b) Write the equation involved in Reimer-Tiemann reaction.

27. frrr srflTlmqrcTi*'A, B silcc*tffiqdrt+.

(i) cHrnrI$eLiA&,nffic

(ii) cH3cooH+L o Brr+KoHr, CHC/r+NaoH

3

A

ETSrT

fqlqfig+er$Hqr(,t t(i) rrtnffimrtFr*rtt,(ii) q+iEq,,oIRttF'I*ffi,(iii) tFffihmr N-ffi'qqqrsii,

6uq€ TrsRFs' rmqrror ffi r;

Give the structures of A, B and C in the following reactions :

(i) cHrBr KCN>R LilHor"ffi"

NH. Br^+KOH CHC/.+NaOH(ii) cH3cooH- ^+

A --r --^; B -^^--3'^'--^^

OR

How will you convert the following :

(i) Nitrobenzene into aniline

(ii) Ethanoic acid into methanamine

(iii) AnilineintoN-phenylethanamide

(Write the chemical equations involved.)

56lllt .,)

Page 293: Chemistry Past Papers

28. (a) fiTqqqistqfrrqrtffi: 2,3(i) dtrd fuqrdffidr (Limiting molar conductivity)

(ii) tqt--f, (Fuel cell)

(b) q6'qtrfi.ti 0.1 dFT t;r qr KC, irr fudffi qa t r $rfir sftriq 100 o t r qftS ti if 0.02 +m rr qr<ur irr KC/ .wr *i .R smr.s2o o *fir t d o.oz *mrt + KC/ + fudrqr 6t qtrfiflr sk dffi qirffir qffiiil dftr+ r 0.1 dil rlrcl kerq;r +t dqre+ar 1.29 x 10-2 Q-r cm-r d* t r

SNTET

(a) N ur iqd €[qtra (electrolysis) sT e6eII lmq ffi | qs'dm gu2+ Effi qt Cuii sqErfrrfr q,+ +ftr+ ffi Wq?st et onqsqqmr &fr t

(b) 298 K q fTq to q;r .*1qfimfufr s1H :

Mg(s) | ug2+10.t M) ll cu2+ (0.01) | cu(s)

tfqr t Ei"u = +2.71V, 1 F = 96500 C mol-l1

(a) Define the following terms :

(i) Limiting molar conductivity

(ii) Fuel cell

O) Resistance of a conductivity cell filled with 0.1 mol L-r KC/ solution is 100 O.If the resistance of the same cell when filled with 0.02 mol I;l KC, solution is520 d2, calculate the conductivity and molar conductivity of 0.02 mol I;1 KCIsolution. The conductivity of 0.1 mol L-l KC/ solution is 1.29 x 10-2 (l-1 cm-I.

OR(a) State Faraday's frst law of electrolysis. How much charge in terms of Faraday is

required for the reduction of 1 mol of Cu2+ to Cu.

O) Calculate emf of the following cell at298KMe(s) | Ms2+(0.1 M) ll Cu2+ (0.01) | Cu(s)

[Given Ei"u = +2.71V, I F = 96500 C mol 1]

2s. (a) eilq+tffiret(i) Mnort IlMnoo ?

(ii) Nqcro+ * NqCrrO, ?

O) qrorleri:

(i) Fe2* *t 6on tt Mn2* +3 eqqsr st ofrtr-fr d+ olfrro*ntr t I

(ii) 3dq'i' *'ten r"r qqi$f zn* ffi ffi+.ur fri tffi rrq$ oqd*t r

(iii) MTsilf,c.n5gii ffi erq€Tr(rg.dorit r

qqt

9

2,rr

56tU1 [P.T.O.

Page 294: Chemistry Past Papers

(i) 3d q,l' *'nq irtr sl 'nq fui qt sTft$nq €nEsES erqrqr( uqd sT flr t r .rr tsr*il qrfdr t r

(ii) 3d q or q*q qr iffi'qur srq Eo(M2+[vI) s'r ffinrrs-qFr rEl-fri t etk eii z

(iii) cp+ silr Mn3* i[ t qil erftrosqo oTrqstsn*.t ekwif z

(iv) d++rggqri*'ssntrsrilqkr** +2 effi3qm €rrytErffi*'Hyfirct r

(v) wqtfiq*Trrft1H: 5

MnOa+8H++5e----+

(a) How do you prepare :

(, IlMnOo from MnO, ?

(ii) NarCrrO, from NarCrOo ?

(b) Account for the following :

(0 Mn2+ is more stable than Fe2+ towards oxidation to +3 state.

(i0 The enthalpy of atomization is lowest for Zn in 3d series of the transitionelemenis.

(iii) Actinoid elements show wide range of oxidation states.

OR(i) Name the element of 3d transition series which shows maximum number of

oxidation states. Why does it show so ?

(i0 which transition metal of 3d series has positive E"(M2+714) value and why ?(iii) Out of Cr3+ and Mn3*, which is a sffonger oxidizing agent and why ?(iv) Name a member of the lanthanoid series which is well known to exhibit +2

oxidation state.

(v) Complete the following equarion :

MnOa+8H++5e---+

30. (a) rq sfutsqroTt61ryme ftrri :

(i) Ctro -H.N_oH H*,

(ii) 2 C6H5CHO + qrq . NaOH ----+

(iii) cH3cooH cl2tP >

O) q)trEii +frEr gii srf,t Eti *'m sre r$qts'Tfti"r ful :

(i) ++d-ons$ki;++.sirr(ii) nit+Ft stTsiH

OPFTT

10

312

56tUt

Page 295: Chemistry Past Papers

(a) w+-*,nqfui'(i) HCN *'srq sFrtffir if cHrcocH, t curcno erftm.fuqrvftm t r

(i0 ffi,FT +16n olqtffim erra erftr*-mrfi €FT rtm t r

(b) B*1 ;1wnt sfufrqrcTf +'ffi ttrflqFffi €qtsr,r ffi :

(i) qriF-tser sTrlqgr

(ii) Nmqr(ii1 +M sfirt*ur

(a) Write the products of the following reactions :

(i) (-)-o +H2N_oH H:\,_J

(ii) 2 C6H'CHO + conc. NaOH->

(iio cH3cooH cl2lP >

(b) Give simple chemical tests to distinguish between the following pairs ofcompounds:

(i) Benzaldehyde and Benzoic acid

(ii) Propanal and hopanone

OR(a) Account for the following :

(i) CH3CHO is more reactive than CHTCOCH3 towards reaction with HCN.

(ii) Carboxylic acid is a stronger acid than phenol.

(b) Write the chemical equations to illustrate the following name reactions :

(i) Wolff-Kishnerreduction

(ii) Aldolcondensation

(iii) Cannizzaroreaction

213

56tUt 11

Page 296: Chemistry Past Papers

1

Qn Answers Marks

1 Oil in water : milk / vanishing cream (any one)

Water in oil : butter / cold cream (any one)

½

½

2 Hydrogen / Iron 1

3 [Co(en)3]3+ : because (en) is a chelating ligand / bidentate ligand ½, ½

4 3-hydroxybutanoic acid / 3-hydroxybutan-1-oic acid 1

5 o – nitrophenol 1

6. Solutions with sameosmotic pressure 1

7. C6H5NH2<(C2H5)2 NH< C2H5NH2 1

8. Amylose 1

9. d=11.2 g/cm3

z=4

a=4x10-8 cm

d=ZxM

Naxa3

11.2 = 4xM

6.022x1023

M =..

M =11.2x6.022x16x10-1

M =107.9gmol-1 or 107.9 u

½

1

½

10 (i) Schottky defect (ii) Decreases (iii Alkali metal halides/ Ionic substances having almost similar size of cations and anions (NaCl/KCl )

1 ½ ½

11 ∆Tf = Kfxw2x1000

w1xM2

0.48K = 5.12Kkgmol-1xW2

75x256x 1000

w2 = 0.48x75x256

5.12x1000

½

1

CHEMISTRY MARKING SCHEME DELHI -2014 SET -56/1/1

x(4x10-8)3

Page 297: Chemistry Past Papers

2

w2= 1.8g ½

12 Solutions which obey Raoult’s law over the entire range of concentration

A-A or B-B ~A-B interactions

∆ Hmix = 0

∆ Vmix = 0

(any one)

1

1

13 (i) Order of reaction is meant for elementary as well as for complex reactions but molecularity is for elementary reactions. (ii) Order can be zero or fraction but molecularity cannot be zero or fraction. (or any other difference)

1

1

14 (i) Impurities are more soluble in melt than in solid state of the metal.

(ii) Different components of a mixture are differently adsorbed on an adsorbent

1

1

15 (i) Ca3 P2 + 6H2O→3Ca(OH)2 + 2PH3

(ii) Cu + 2H2 SO4→CuSO4 + 2H2O+ SO2

(give full credit even if correct products are mentioned)

1

1

OR 15 (i) HI < HBr < HCl < HF

(ii) H2O< H2S < H2Se< H2Te

1

1

16 (i) Tetraamminedichloridochromium (III) ion

(ii) Geometrical isomerism / cis – trans

1

1

17 (i) (b) is chiral OR

(a) undergoes faster SN2

(ii) (a) SN2

(b) SN1

1

½, ½

18 (i)

(ii)

1

1

19

(a) $

% = Kp 1 n' or log (x/m)= log K + 1/n log p

(b) Reversible in nature/ stable sol/ solvent loving (or any other)

(c) Associated colloid – Soap/ micelles;Multimolecular colloid - S8/ gold sol. (or any other)

1

1

½, ½

Cl

CH2 – CH2 – CH2 Br

Page 298: Chemistry Past Papers

3

20 a) (i) (ii)

1+1

b) White phosphorus Red phosphorus

It exists as discrete tetrahedral P4unit It exists in the form of polymeric chain. 1

OR correct structures.

21 (i) Because +5 oxidation state is more covalent than +3/ high charge to size ratio / high

polarizing power

(ii) Because HCl is a mild oxidising agent/ formation of hydrogen gas prevents the formation of

FeCl3 .

(iii) Because of resonance in O3 molecule.

1

1

1

22 SO2 Cl2→ SO2+ Cl2

At t = 0s0.4 atm 0 atm0 atm

At t = 100s (0.4 – x) atm x atm x atm

Pt = 0.4 – x + x + x

Pt = 0.4 + x

0.7 = 0.4 + x

x = 0.3

k = 2.303

t log

)*

)*+),

k = 2.303

t log

0.4

0.8-0.7

k = 2.303

100 log

0.4

0.1

k = .--

x 0.6021 = 1.39 x 10-2s-1

1

1

1

23 (a) carbohydrates, lipids, proteins, enzymes, nucleic acids (any two)

(b) Antiseptics are the chemical substances which are used to kill or prevent the growth of

microbes. Eg – Dettol / Iodoform / Boric acid/ phenol (or any other correct example)

(c) Becasuse it is unstable at cooking temperature.

½, ½

½, ½

1

24 (a) Vitamin A 1

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4

(b) Uracil

(c) It suggests that six carbon atoms are in straight chain / CHO – (CHOH)4 – CH2OH

1

1

25 (i) Concern towards environment / caring / socially aware / team work. (atleast two values)

(ii) Polymers which can be degraded by the action of microorganisms. Eg. PHBV , Nylon -2-

nylon- 6/ any natural polymer

(iii) Addition polymer.

1

1

1

26 (a) HBr → H+ + Br-

Or

( where R = -CH3)

(b)

½

½

1

1

27 (a)

(b)

½+½+

½

½+½+

½

OR

CH3 COOH NH3 CH3 CONH2 Br2 CH3 NH2 CHCl3 CH3 NC ∆ A KOH B NaOH C

CH3 Br KCN CH3 CN LiAlH4 CH3 CH2 NH2 HNO2 CH3 CH2 OH A B 273K C

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5

27 (i)

(ii)

(iii)

( Or by any other suitable method.)

1

1

1

28 (a) (i) Limiting molar conductivity – when concentration approches zero the conductivity is

known as limiting molar conductivity

(ii) Fuel cell – are the cells which convert the energy of combustion of fuels to electrical energy.

(b)

1

1

1

1

1

OR

28 (a) The amount of substance deposited at any electrode during electrolysis is directly

proportional to the quantity of electricity passed through the electrolyte. (aq. Solution or melt)

Charge = Q = 2F

(b) E cell = E0 cell – 0.059

n log

[Mg2+]

[Cu2+]

1

1

1

½

Sn/HCl

NO2 NH2

CH3 COOH CH3 CONH2 Br2 CH3 NH2 NH3 +KOH

(CH3CO)2O

∥ O

NH – C- CH3

NH2

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6

E cell = 2.71 - 0.059

2 log

0.10

.

E cell = 2.71 – .67

log 10

= 2.71 – 0.0295 = 2.68 V

½

1

29 (a) (i)

(ii)

(b) (i) Because of 3d5(half filled) stable configuration of Mn2+

(ii) Because in zinc there is no unpaired electron / there is no contribution from the inner d

electrons.

(iii) Because of comparable energies of 7s, 6d and 5f orbitals

1

1

1

1

1

OR

29 (i) Mn , because of presence of 5 unpaired electrons in 3d subshell

(ii) Cu , because enthalpy of atomization and ionisation enthalpy is not compensated by enthalpy

of hydration.

(iii) Mn 3+, because Mn2+ is more stable due to its half filled (3d5)configuration

(iv) Eu+2(Eu)

(v)

½ + ½

½ + ½

½ + ½

1

1

30 (a)

(i)

(ii)

(iii) Cl - CH2 - COOH

(b) (i) Add NaHCO3, benzoic acid will give brisk effervescence whereas benzaldehyde will not

1

1

1

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7

give this test. (or any other test)

(ii) Add tollen’s reagent , propanal will give silver mirror whereas propanone will not give this

test. (or any other test)

1

1

OR

30 (a) (i) Because the positve charge on carbonyl carbon of CH3 CHO decreases to a lesser extent

due to one electron releasing(+I effect) CH3 group as compared to CH3 COCH3(two electron

releasing CH3 group) and hence more reactive.

(ii) Because carboxylate ion (conjugate base) is more resonance stablized than phenoxide ion.

(b) (i)

(ii)

(or any other example)

(iii)

(or any other example)

1

1

1

1

1

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CBSE Annual Examination Question Paper 2013

CHEMISTRY (THEORY)

Time allowed: 3 hours] [Maximum marks: 70

General Instructions:

(i) All questions are compulsory.

(ii) Question Nos. 1 to 8 are very short-answer type questions and carry 1 marks

each.

(iii) Question Nos. 9 to 18 are short-answer type questions and carry 2 marks each.

(iv) Question Nos. 19 to 27 are also short-answer type questions and carry 3 marks

each.

(v) Question No. 28 to 30 are long-answer questions and carry 5 marks.

(vi) Use Log Table, if necessary. Use of calculators is not allowed.

___________________________________________________________________________________________________________

1. How many atoms constitute one unit cell of a face-centered cubic crystal?

2. Name the method used for the refining of Nickel metal.

3. What is the covalency of nitrogen in N2O5?

4. Write the IUPAC name of

5. What happens when CH3-Br is treated with KCN?

6. Write the structure of 3-methyl butanal.

7. Arrange the following in increasing order of their basic strength in aqueous solution:

CH3.NH2,(CH3)3N,(CH3)2NH

8. What are three types of RNA molecules which perform different functions?

9. 18g of glucose, C6H12O6 (Molar Mass= 180g mol-1) is dissolved in 1Kg of water in a

sauce pan. At what temperature will this solution boil?

10. The conductivity of 0.20 M solution of KCl at 298 K is 0.025 S cm-1. Calculate its molar

conductivity.

11. Write the dispersed phase and dispersion medium of the following colloidal system:

(i) Smoke (ii) Milk OR

What are lyophilic and lyophobic colloids? Which of these sols can be easily

coagulated on the addition of small amounts of electrolytes?

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12. Write the differences between physisorption and chemisorption with respect to the

following:

(i) Specificity

(ii) Temperature dependence

(iii) Reversibility and

(iv) Enthalpy change

13. (a) Which solution is used for the leaching of silver metal in the presence of air in

the metallurgy of silver?

(b) Out of C and CO, which is a better reducing agent at the lower temperature

range in the blast furnace to extract iron from the oxide ore?

14. What happens when

(i) PCl5 is heated?

(ii) H3PO3 is heated?

Write the reaction involved.

15. (a) Which metal in the first transition series (3d series) exhibits +1 oxidation state

most frequently and why?

(b) Which of the following cations are colored in aqueous solutions and why?

Sc3+,V3+,Ti4+,Mn2+

(At. nos. Sc = 21, V= 23, Ti = 22, Mn = 25)

16. Chlorobenzene is extremely less reactive towards a nucleophilic substitution reaction.

Give two reasons for the same.

17. Explain the mechanism of the following reaction:

18. How will you convert:

(i) Propene to Propan-2-ol?

(ii) Phenol to 2, 4, 6 – trinitrophenol?

19. (a) What type of semiconductor is obtained when silicon is doped with boron?

(b) What type of magnetism is shown in the following alignment of magnetic

moments?

(c) What type of point defect is produced when AgCl is doped with CdCL2?

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20. Determine the osmotic pressure of a solution prepared by dissolving 22.5 10 g−× of

K2SO4 in 2L of water at 25 C , assuming that it is completely dissociated.

(R=0.0821 L atm K-1mol-1, Molar mass of K2SO4=174g mol-1).

21. Calculate the emf of the following cell at 298 K:

22( ) (0.001 ) ( ) ( )(1 ), ( )Fe s Fe M H g H g bar Pt s+ +

( 0.44 )cellGiven Vο = +

22. How would you account for the following?

(i) Transition metals exhibit variable oxidation states.

(ii) Zr (Z=40) and Hf (Z=72) have almost identical radii.

(iii) Transition metals and their compounds act as catalyst.

OR

Complete the following chemical equations:

(i) 2 22 7 6 14Cr O Fe H− + ++ + →

(ii) 242 2CrO H− ++ →

(iii) 24 2 42 5 16MnO C O H− − ++ + →

23. Write the IUPAC names of the following coordination compounds:

(i) [Cr(NH3)3Cl3]

(ii) K3[Fe(CN)6]

(iii) [CoBr2(en)2]+, (en = ethylenediamine)

24. Give the structures of A, B and C in the following reactions:

(i)

(ii)

25. Write the names and structures of the monomers of the following polymers:

(i) Buna-S

(ii) Neoprene

(iii) Nylone-6, 6

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26. After watching a programme on TV about the adverse effects of junk food and soft

drinks on the health of school children, Sonali, a student of Class XII, discussed the

issue with the school principal. Principal immediately instructed the canteen

contractor to replace the fast food with the fibre and vitamins rich food like sprouts,

salad, fruits etc. This decision was welcomed by the parents and the students.

After reading the above passage, answer the following questions:

(a) What values are expressed by Sonali and the Principal of the school?

(b) Give two examples of water-soluble vitamins.

27. (a) Which one of the following is a food preservative?

Equanil, Morphine, Sodium benzoate

(b) Why is bithional added to soap?

(c) Which class of drugs is used in sleeping pills?

28. (a) A reaction is second order in A and first order in B.

(i) Write the differential rate equation.

(ii) How is the rate affected on increasing the concentration of A three

times?

(iii) How is the rate affected when the concentration of both A and B are

doubled?

(b) A first order reaction takes 40 minutes for 30% decomposition. Calculate t1/2

for this reaction.

(Given log 1.428=0.1548)

OR

(a) For a first order reaction, show that time required for 99% completion is twice

the time required for the completion of 90% of reaction.

(b) Rate constant ‘k’ of a reaction varies with temperature ‘T’ according to the

equation: 1

log log2.303

aEk A

R T = −

Where Ea is the activation energy. When a graph is plotted for log k Vs.1

T, a

straight line with a slope of -4250 K is obtained. Calculated ‘Ea’ for the reaction.

(R=8.314 JK-1mol-1)

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29. (a) Give reasons for the following:

(i) Bond enthalpy of F2 is lower than that of Cl2.

(ii) PH3 has lower boiling point than NH3.

(b) Draw the structures of the following molecules:

(i) BrF3 (ii) (HPO3)3

OR

(a) Account for the following:

(i) Helium is used in diving apparatus.

(ii) Fluorine does not exhibit positive oxidation state.

(iii) Oxygen shows catenation behavior less than sulphur.

(b) Draw the structures of the following molecules.

(i) XeF2 (ii) H2S2O8

30. (a) Although phenoxide ion has more number of resonating structures than

Carboxylate ion, Carboxylic acid is a stronger acid than phenol. Give two

reasons.

(b) How will you bring about the following conversions?

(i) Propanone to propane

(ii) Benzoyl chloride to benzaldehyde

(iii) Ethanal to but-2-enal

OR

(a) Complete the following reactions:

(i)

(ii)

(iii)

(b) Give simple chemical tests to distinguish between the following pairs of

compounds:

(i) Ethanal and Propanal (ii) Benzoic acid and Phenol

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1

Marking Scheme Chemistry

Delhi- SET (56/1/1) 1 6:6 or 6 1

2 The sum of powers of the concentration terms of the reactants in the rate law expression is called the order of that chemical reaction. Or rate = k[A]p[B]q Order of reaction = p+q

1

3 Due to unbalanced bombardment of the colloidal particles by the molecules of the dispersion medium.

1

4 NO2+

1

5 2,5-Dimethylhexane -1,3-diol. 1 6. (CH3)2CHCOOH < CH3CH(Br)CH2COOH < CH3CH2CH(Br)COOH 1

7. C6H5N

+Cl - + KI C6H5I + KCl + N2 1

8. Phenol (or any other correct one) 1

9. Aryl halides are less ractive towards nucleophilic substitution because of any of the following reasons with correct explanation:

(i) Resonance effect stabilization (ii) sp2 hybridization in haloarenes being more electronegative than sp3 in haloalkanes. (iii) Instability of phenyl cation which is not stabilized by resonance. (iv) possible repulsion between electron rich nucleophile and electron rich arene

(atleast two reasons to be given ) OR

(i) CH3I, Because iodine is a better leaving group due to its larger size. (ii) CH3Cl,the presence of bulky group on the carbon atom in (CH3)2CCl has an inhibiting effect.

2 1 1

10 (a) 1-Bromobut-2-ene (b) CH3CH2CH2CH2Br

1 1

11 Henry’s law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas over the solution. Applications

(i) To increase the solubility of CO2 in soft drinks and soda water, the bottle is sealed under high pressure.

(ii) Scuba divers must cope with high concentrations of dissolved Nitrogen with breathing air at high pressure underwater.To avoid this air is diluted with He.

(iii) At high altitudes the partial pressure of oxygen is less than that at the ground level. Low blood oxygen causes anoxia.

(any two)

1 1

2

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2

12

k = 2.303 log [ A0 ] t [A] k = 2.303 log 100 40min 70 k = 2.303 x 0.155 = 0.00892min-1 40 t1/2

= 0.693 k

t1/2

= 0.693 min 0.00892 t1/2 = 77.7min

½ ½ 1

13

Rate constant ‘k’ of a reaction is defined as the rate of reaction when the concentration of the reactant(s) is unity. / or Rate constant is the proportionality factor in the rate law. (i) Unit for ‘k’ for a zero order reaction = mol L-1 s-1 (ii) Unit for ‘k’ for a first order reaction = s-1

1 ½ ½

14 (i) Peptide linkage: Peptide linkage is an amide (-CO-NH-) bond formed between –COOH and –NH2 group in protein formation.

(ii) Denaturation: When a protein in its native form, is subjected to physical change like change in temperature or chemical change like change in pH,protein loses its biological activity. This is called denaturation of protein.

1 1

15

*

(i) Despite having the aldehyde group, glucose does not give 2,4-DNP test or Schiff’s test. (ii) It does not form the hydrogensulphite addition product with NaHSO3.

(iii) The pentaacetate of glucose does not react with hydroxylamine indicating the absence of free –CHO group. (any two)

1+1

16 (i)The lone pair of electrons on N atom in NH3 is directed and not diffused / delocalized as it is in PH3

due to larger size of P/ or due to availability of d-orbitals in P. (ii) S2 molecule like O2, has two unpaired electrons in antibonding π* orbitals.

1+1

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17

SF4 XeF4

1 1

18. Biodegradable detergents are those detergents which are easily degraded by the micro-organisms and hence are pollution free. ex. Soap / Sodium laurylsulphate / any other unbranched chain detergent. (any one) Non Biodegradable Detergents are those detergents which cannot be degraded by the bacteria easily and hence create pollution. [example not essential]

½ ½ 1

19 The solids with intermediate conductivities between insulators and conductors are termed semiconductors.

(i) n- type semiconductor : It is obtained by doping Si or Ge with a group 15 element like P. Out of 5 valence electrons , only 4 are involved in bond formation and the fifth electron is delocalized and can be easily provided to the conduction band. The conduction is thus mainly caused by the movement of electron.

(ii)p – type semi conductor : It is obtained by doping Si or Ge with a group 13 element like Gallium which contains only 3 valence electrons. Due to missing of 4th valence electron,electron hole or electron vacancy is created The movement of these positively charged hole is responsible for the conduction.

1 1

1

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20

∆ Tf = Kf m No. of moles of glucose = Molality of Glucose solution = ∆ Tf = Kf m = 1.86 K kg mol-1 x 1.20 mol kg –1 = 2.23 K Temperature at which solution freezes =( 273.15 – 2.23K = 270.77K or -2.230C Or (273.000 – 2.23)K = 270.7 K

1 1 1

21 Lyophilic sols are solvent attracting sols ex. Gum,gelatine,starch,rubber (any one) Lyophobic sols are solvent repelling sols ex. Metal sols,metal sulphides (any one) Lyophobic sols are readily coagulated because they are not stable.

½+½ ½+½

½+½

22

(i) Froth floatation process: This method is based on the difference in the wettability of the mineral particles (sulphide ores)and the gangue particles.The mineral particles become wet by oils while the gangue particles by water and hence gets separated.

(ii) Zone refining: This method is based on the principle that the impurities are more soluble in the melt than in the solid state of metal.

(iii) Refining by Liquation:The method is based on the lower melting point of the metal than the impurities and tendency of the molten metal to flow on the sloping surface.

1 1 1

54 g 180 g mol -1

1000 250kg

= 1.20mol kg-1 54 mol x 180

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23 (i)3Cl2+6NaOH 5NaCl+NaClO3+3H2O (ii)4H3PO3 3H3PO4+PH3

(iii)Xe+[PtF6]-

OR (i)Ca3P2(s)+ 6H2O(l)3Ca(OH)2(aq) + 2PH3(g) (ii)Cu2+(aq)+ 4NH3(aq)[Cu(NH3)4]

2+(aq) (iii)2F2(g)+ 2H2O(l) 4H+ (aq) + 4F-(aq) + O2(g)

1x3=3

24

* (a) Ligand: The ions or molecules bound to the central atom/ion in the

coordination entity are called ligands. ex. of bidentate ligand- ethane-1,2-diamine or oxalate ion

(or any other) (b)* In [Ni(CN)4]

2-, nickel is Ni2+, (3d8),with strong Ligand like CN-, all the electrons are paired up in four d-orbitals resulting into dsp2 hybridization giving square planar structure and diamagnetic character. In Ni(CO)4:, nickel is in zero valence state , (3d84s2),with strong Ligand like CO,4s2,electrons are pushed to the d-orbitals resulting into sp3 hybridization giving tetrahedral shape and diamagnetic in nature. (or this can be explained by drawing orbital configurations too.)

½,½ 1 1

25 (i) PCC, KMnO4,CrO3 (any one) (ii) LiAlH 4,NaBH4 (any one) (iii)aqueous Br2

(or any other suitable reagent)

1X 3=3

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6

26

(i) It is because in aniline the –NH2 group is attached directly to the

benzene ring.It results in the unshared electron pair on nitrogen atom to be in conjugation with the benzene ring and thus making it less available for protonation. (or any other suitable reason)

(ii) Methyl amine in water gives OH- ions which react with FeCl3 to give precipitate of ferric hydroxide/ or

CH3NH2 + H2O CH3NH3OH- CH3NH+

+OH- Fe3+ + 3OH- Fe (OH)3

(iii)Aniline does not undergo Friedel-Crafts reaction due to salt formation with aluminium chloride, the Lewis acid.

1X 3=3

27 (i) Buna-S : 1,3- Butadiene and Styrene CH2 = CH – CH = CH2 and (ii) Neoprene:Chloroprene CH2 = C – CH = CH2 (iii) Nylon-6: Caprolactum

½+½ ½+½ ½+½

3

+

Cl

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7

28

*

Λm = κ c

= 7.896 x 10-5 S cm-1 x 1000 cm3L-1 0.00241 molL-1 = 32.76 Scm2 mol-1

Λm

Λm0

=32.76 Scm2 mol-1

390.5 Scm2 mol-1 = 0.084 Scm2 mol-1

= 0.00241 X (0.084)2 =1.7 X 10 or 1.865 x 10 (if α is not neglected)

OR

Ag+ + e- Ag 108 g is deposited by 96500C electric charge 1.45 g of silver is deposited by 96500C x 1.45 g = 1295.6 C 108 g Quantity of electricity passed = Current x t t = 1295.6C = 863.7 s 1.5 amp Cu2+ + 2e- Cu 2 x 96500 C deposits 63.5 g of Cu 1295.6 C deposits 63.5g x 1295.6 C of Cu 2 x 96500 C = 0.426 g of Cu

1 1 1 1 1 1 1 1 1

α =

= C α2 C

α2

C(1- α) K =

-5 -5

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8

29

*

Zn2+ + 2e- Zn 2 x 96500 C deposits 65.4 g of Zn 1295.6 C deposits 65.4g x 1295.6 C of Zn 2 x 96500 C = 0.44 g of Zn

(or any other suitable method)

(i) Because of larger number of unpaired electrons in their atoms they have stronger interatomic interaction and hence stronger bonding between atoms resulting in higher enthalpies of atomisation.

(ii) Because of their ability to adopt multiple oxidation states and to form

complexes. (iii) Because of poorer shielding by 5f electrons than that by 4f , actinoid

contraction is greater than the lanthanoid contraction. (iv) Much larger third inonisation energy of Mn( where the required change

is d5 to d4) is mainly responsible for this. (v) Because of the presence of incomplete d-orbital (3d14s2) in its ground

state.

OR

3d34s2(Vanadium): Oxidation states +2,+3,+4,+5 Stable oxidation state: +4 as VO2+ ,+5 as VO4

3-

3d54s2(Manganese): Oxidation states +2,+3,+4,+5,+6,+7 Stable oxidation states: +2 as Mn2+ ,+7 as MnO-

4

3d64s2(Iron): Oxidation states +2,+3 Stable oxidation state: +2 in acidic medium, +3 in neutral or in alkaline medium.

(b) (i) 4FeCr2O4 + 8Na2CO3 + 7O2 8 Na2CrO4 + 2 Fe2O3 + 8 CO2

(ii) 2MnO2 + 4KOH + O2 2K2MnO4 + 2H2O

1 1x5=5 1x3=3 1+1

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30 (a) (i) (ii) BH3, H2O2 / OH-, PCC (any two) (iii) (NOTE:any two correct answers to be evaluated and 1½ marks for each to be awarded)

(b) (i) Cannizzaro reaction: Aldehydes which do not have an α-hydrogen atom, uhdergo self oxidation and reduction reaction on treament with concentrated alkali.

(or any other suitable reaction)

1½+1½ 1

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10

(ii) Cross aldol condensation: When aldol condensation is carried out between two different aldehydes and /or ketones, it is called Cross aldol condensation

(or any other suitable reaction) (Note: Award full marks for correct chemical equation;award ½ mark if only statement is written)

OR

(i) Because two alkyl groups in ketones reduce the positive charge on carbon atom of the carbonyl group more effectively than in aldehydes. / or sterically, the presence of two relatively large substituents in ketones hinders the approach of nucleophile to carbonyl carbon than in aldehydes having only one such substituents.

(ii) Beacuase of the absence of hydrogen bonding in aldehydes and ketones.

(iii) Because of the presence of the sp2 hybridised orbitals(or π-bond) of carbonyl carbon.

1 1x3=3

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11

(b) (i)Acetaldehyde and benzaldehyde : Acetaldehyde gives yellow ppt of Iodoform(CHI3)on addition of NaOH / I2 whereas benzaldehyde does not give this test. ( or any other suitable test)

(ii) Propanone and propanol : Propanone gives yellow ppt of Iodoform(CHI3)on addition of NaOH / I2 whereas propanol does not give this test. Or / Propanol gives brisk effervesence on adding a piece of Sodium metal whereas Propanone does not give this test. ( or any other suitable test)

1+1

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1

Marking Scheme Chemistry

Delhi- SET (56/1/2) 1 4 1

2 In primary battery the reaction occurs only once and after use over a period of time becomes dead. Leclanche cell or Dry cell is an example.

½+½

3 Q.3 Set 1 1

4 Q.4 Set 1 1

5 Q.5 Set 1 1

6. Pentane -2, 4 –dione

1

7. Q.7 Set 1 1

8. Q.8 Set 1 1

9 Raoult’s law states that for a solution of volatile liquids, the partial vapour pressure of each component in the solution is directly proprtional to its mole fraction. When the solute-solvent interaction is weaker than those between the solute-solute and solvent-solvent molecules than solution shows positive deviation from Raoults law because the partial pressure of each component is greater. ex. mixture of ethanol and acetone or carbondisulphide and acetone behave in this manner. When the solute-solvent interaction is stronger than those between the solute-solute and solvent-solvent molecules than solution shows negative deviation from Raoults law and the partial vapour pressure of each component is lower. ex. mixture of chloroform and acetone behave in this manner. (Note: Explaination with suitable example of any one of the two.)

OR The extra pressure applied on the solution side that just stops the flow of solvent to solution through semi-permeable membrane is called osmotic pressure of the solution.

Here π is the osmotic pressure and R is the gas constant. Thus knowing the quantities w2, T, π and V we can calculate the molar mass of the solute.

1 ½ ½ 1 1

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2

10 Λm = κ x 1000 cm3L-1 c = 0.0248 S cm-1 x 1000 cm3 L-1 = 24.8 S cm2 0.20 mol L-1 0.20 mol Λm = 124 Scm2 mol-1

1 1

11 The galvanic cell is depicted as: Zn(s)| Zn2+(aq) || Ag+(aq)|Ag (s)

(i) Zinc electrode is negatively charged (ii) The ions formed i.e Zn2+ and Ag+ in the solution are the carriers of the

current within the cell. (iii) At anode: Zn(s)Zn2+(aq) + 2e-

At cathode: 2Ag+(aq)+ 2e- 2Ag(s)

½ ½ ½ ½

12 Q.14 Set 1

2

13

Q.15 Set 1

2

14 (i) C6H5I + KCl + N2 (ii) BrCH2-CH2Br

1+1

15 (i) Aryl halides are less ractive towards nucleophilic substitution because of any of the following reasons

(i) Resonance effect stabilization (ii) sp2 hybridization in haloarenes and sp3 in haloalkanes. (iii) Instability of phenyl cation (iv) possible repulsion

(ii) Cl Undergoes SN1 reaction faster because of the stability of secondary carbocation.

1 ½+½

16 Q.18 Set 1 2 17 Q.16 Set 1

2

18

Q.17 Set 1

2

19 Q.21 Set 1 3 20 Q.20 Set 1 3 21 Q.19 Set 1 3

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3

22 Q.23 Set 1 3 23 Q.22 Set 1 3 24 Q.26 Set 1 3 25 Q.27 Set 1 3 26 Q.25 Set 1 3 27 Q.24 Set 1 3 28

*

(a) Half life of a First order reaction:

(b) 2NH3 (g) N2 (g) +3 H2(g) Rate = -d[NH3] =k[NH3]

O = 2.5 x10-4Ms-1 dt - 1 d[NH3] = + d[N2] = + 1 d[H2] 2 dt dt 3 dt Rate of production of N2 = + d[N2] = - 1 [NH3] dt 2 dt = 1 x (2.5 x 10-4 Ms-1) = 1.25 x 10-4 Ms-1

2 Rate of production of hydrogen = d[H2] = - 3 [NH3] dt 2 dt = 3 x (2.5 x 0-4 Ms-1) 2 = 3.75 x 10-4 Ms-1

1/2 1/2 1 1 1 1

or

Rate = -d[NH3] =k[NH3]O = 2.5 x10-4Ms-1

dt Rate = - 1 d[NH3] = + d[N2] = + 1 d[H2] 2 dt dt 3 dt Rate of production of N2 = + d[N2] = Rate= 2.5 x10-4Ms- dt

1 1

0

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4

Rate of production of hydrogen = d[H2] = 3 x Rate dt = 3 x (2.5 x 0-4 Ms-1) = 7.5 x 10-4 Ms-1 (Note: No marks to be deducted for wrong unit in this question,as there is a misprint in the question in units of k)

or (a)Factors affecting rate of chemical reaction are: (i)Concentration of reactants (ii)Temperature (iii)Presence of catalyst (iv)Surface Area (v)Activation energy (any four)

(b) k = 0.693 t1/2

k = 0.693 5730 y K = 1.21 x 10-4 y-1 t = 2.303 log [ A0 ] k [A] k = 2.303 log 100 1.21 x 10-4 y-1 80 k = 2.303 log 1.25 1.21 x 10-4 y-1

k = 2.303 x 0.0969 1.21 x 10-4 y-1

= 1845 years

1 ½x4=2 ½ ½ 1 1

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29

*

(or any other suitable method)

(a) (i)Decarboxylation: Carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are heated with sodalime.The reaction is known as decarboxylation.

R-COONa NaOH & CaO R-H + Na2CO3

Heat (ii) Cannizzaro reaction: Aldehydes which do not have an

α-hydrogen atom, uhdergo self oxidation and reduction reaction on treament with concentrated alkali.

( or any other suitable reaction)

(Note: Award full marks for correct chemical equation;award ½ mark if only statement is written)

1x3=3 1+1

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30

OR (a) (i)

C 69.77/12 5.81 5.81/1.16 5 H 11.63/1 11.63 11.63/1.16 10 O 18.60/16 1.16 1.16/1.16 1

Empirical formula C5H10O,empirical formula mass 60+10+16=86 Hence, Mol formula C5H10O It is a ketone as it appears from its reactions which on oxidation gives ethanoic and propanoic acids, hence the compound is CH3COCH2CH2CH3 (b)(i)Because the stability of conjuguate base of monochloroethanoic acid is less due to presence of one electron withdrawing -Cl group than in dichloroethanoic acid. (ii)This is because of greater electronegativity of sp2 hybridised carbon to which carboxyl carbon is attached. ( or any other suitable reason)

Q.29 Set 1

1 1 1 1+1 5

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1

Marking Scheme Chemistry

Delhi- SET (56/1/3)

1 In which the alignment of domains (moments) is in a compensatory way to give zero net moment.

1

2 Λm = κ where Λm is molar conductivity , κ is conductivity c c is concentration in mol L-1

1

3 Chemisorption

1

4 Q.5 Set 1 1

5 Q.4 Set 1 1

6 Q.8 Set 1 1

7 Q.6 Set 1 1

8 Q.7 Set 1 1

9 Q.11 Set 2 2

10 R= ρ( l / A ) Cell constant, l/A = R/ρ = Rκ = Resistance x Conductivity =(1500 Ω) x (0.146 x 10-3 S cm-1) = 0.219 cm-1

1 1

11 Q.9 Set 2

2

12 Q.16 Set 1

2

13

Q.17 Set 1

2

14 Q.9 Set 1 2 15 Q.10 Set 1 2 16 Q.18 Set 1 2 17 Q.14 Set 1

2

18

Q.15 Set 1 2

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19

1x3=3 6x½=3

20 Q.20 Set 1

3

21 (i) Zone refining: This method is based on the principle that the impurities are more soluble in the melt than in the solid state of metal.

(ii) Vapour phase refining: In this method, the metal is converted into its volatile compound and collected elsewhere. It is then decomposed to give pure metal.

(iii) Electrolytic refining: In this method, the impure metal is made to act as anode. A strip of the same metal in pure form is used as cathode. They are put in a suitable electrolytic bath containing soluble salt of the same metal.The more basic metal remains in the solution and the less basic ones go to the anode mud

1x3=3

22 (i) Ferric hydroxide sol is positively charged. By adding potassium chloride, the excess chloride ions neutralize its positive charge and cause it to coagulate.

(ii) The dispersed phase and dispersion medium migrate towards oppositely charged electrodes (electrophoresis).

(iii) The beam of light is scattered by colloidal particles(Tyndall effect).

1x3=3

23 Q.27 Set 1

3

24 Q.26 Set 1

3

25

Q.24 Set 1

3

26 Q.25 Set 1

3

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27 Q.23 Set 1

3

28

Q.29 Set 1

5

29

Q.28 Set 2

5

30

Q.30 Set 1

5


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