anoraganik 1-lkm-asam basa -bu am
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TEORI ASAM BASA
A. Pengetahuan Prasyarat
Sebelum anda mulai mengikuti pokok bahasan asam basa ini, Anda harus
telah memiliki pengetahuan tentang :
1. Pemberian tata nama senyawa kimia
2. Penulisan konfigurasi elektron
3. Penulisan rumus molekul dan struktur molekul
4. Sifat-sifat umum keperiodikan unsur pada susunan berkala, yang meliputi :
jari-jari atom, muatan inti, shielding effect, energi ionisasi dan
keelektronegatifan unsur
5. Jenis-jenis ikatan kimia dan gaya-gaya kimia
6. Penulisan bilangan oksidasi
B. Tujuan
Setelah mempelajari teori asam-basa diharapkan mahasiswa dapat :
1. Menjelaskan teori asam basa Arrhenius
2. Menjelaskan teori asam basa Bronsted –Lowry
3. Menjelaskan teori asam basa Lewis
4. Menjelaskan konsep asam basa Lux dengan disertai contoh
5. Menjelaskan perbedaan di antara teori-teori asam-basa yang telah diberikan
6. Menjelaskan pengertian asam protonik
7. Menjelaskan fenomena afinitas proton asam protonik
8. Menjelaskan pengaruh pelarut
9. Menyebutkan beberapa konsep reaksi asam-basa nonprotonik
10.Menjelaskan kekuatan relatif asam basa Lewis berdasarkan posisinya dalam
tabel periodik
11.Menjelaskan kekuatan relatif asam basa Lewis berdasarkan efek substituent
12.Menjelaskan kekuatan relatif asam basa Lewis berdasarkan efek sterik
13.Menjelaskan teori asam basa keras lunak
C. Pengantar
Dalam paket ini akan kita pelajari sifat asam basa suatu molekul dengan
berbagai pendekatan teori asam basa
Latihan 1 (Tujuan 1)
Lembar Kerja Mahasiswa Teori Asam Basa
1. Meskipun ada kritikan-kritikan, teori Arrhenius tentang perilaku asam-
basa dapat menjelaskan secara memuaskan reaksi asam-basa di dalam
larutan air. Mengapa ?
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Latihan 2 (Tujuan 2)
2a. Berikan penjelasan teori asam basa menurut Bronsted – Lowry
dengan
disertai contoh-contoh
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b. Tunjukkan basa konjugasi dari asam – asam berikut : HSO4 -, CH3OH,
H2PO4-, Si(OH)4 , HS- , [Co(NH3) (OH2)]3+
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c. Tunjukkan urutan kekuatan basa berikut :
i. HCO3- , CO3
2- :
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ii. PO43- , SO4
2-, ClO4- :
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Latihan 3 (Tujuan 3)
3. a. Berikan penjelasan teori asam-basa menurut Lewis
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b. Jelaskan mengapa teori asam basa Lewis dapat digunakan untuk
menerangkan ikatan koordinasi ?. Berikan contoh untuk jawab anda !
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Latihan 4 (Tujuan 4)
4. Apakah sistem asam basa Lux – Flood itu ? Apakah lebih baik atau
kurang baik dibanding dengan konsep Bronsted – Lowry ?
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Latihan 5 (Tujuan 5)
5. Berikan perbedaan dengan menunjukkan kelebihan masing-masing
teori asam basa yang anda ketahui
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Latihan 6 ( Tujuan 6)
6a. Berikan pengertian asam protonik dan berikan contoh-contoh
untuk penjelasan anda !
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b. Pada setiap pasangan asam berikut, ramalkan manakah asam
protonik yang lebih kuat dan berikan alasan dari yang anda pilih !
i . Asam selenat atau asam sulfat :
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ii H2S atau H2Te :
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iii. HOBr atau HOCl:
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iv. SnH4 atau SbH3 :
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v. [Fe(H2O)6]3+ atau [Fe(H2O)6]2+ :
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c. Pada setiap pasangan basa berikut, ramalkan mana yang lebih kuat
dalam larutan air dan berikan alasan pada pilihan anda !
i. Potasium hidroksida atau kalsium hidroksida
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ii. Berilium hidroksida atau stronsium hidroksida :
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Latihan 7 (Tujuan 7)
7. Berikan penjelasan tentang afinitas proton asam protonik !.
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Latihan 8 (Tujuan 8)
8a. Bagaimanakah pengaruh pelarut terhadap sifat asam dan basa
suatu senyawa
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b. Meskipun begitu banyak skala pengukuran kualitas keasaman dan
kebasaan, ternyata bahwa skala-skala pengukuran itu semuanya
mengarah kepada hasil yang sama. Bila demikian, bagaimanakah
Anda menjelaskan hasil pengamatan bahwa asam cuka dan asam
nitrat keduanya bersifat asam dalam larutan air, dan basa dalam
larutan asam sulfat ?
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Latihan 9 (Tujuan 9)
9. Sebutkan beberapa konsep reaksi asam basa non protonik ! Berikan
Contoh-contoh !
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Latihan 10 ( Tujuan 10 )
10a. Berikan penjelasan kekuatan relatif asam dan basa Lewis
berdasarkan posisinya dalam susunan berkala unsur !
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Latihan 11 (Tujuan 11)
11 a. Susunlah zat-zat berikut ini dalam urutan kenaikan kekuatan
asam Lewis, dengan argumentasi:
i. BF3, BCl3, BBr3, BI3 :
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ii. B2H6, B(CH3)3, B(Ph3) 3 :
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iii. BeCl2, BCl3 :
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11 b. Susunlah basa-basa berikut ini dalam urutan kenaikan kekuatan
basanya :
i. Me3N , Et3 N :
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ii . 2-MePy , 4-MePy (Py= piridin) :
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Latihan 12 (Tujuan 12)
12. Berikan penjelasan mengapa pada pembentukan trimetilboran
dengan
a) piridin , b) 2 metil piridin dan c) 2 – ( t- butil )- piridin menunjukkan
panas reaksi ( ΔHr ) masing-masing sebagai berikut : -42, -74 dan
85 kJ ?
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Latihan 13 (Tujuan 13)
13. Berikan penjelasan konsep asam basa keras dan lunak dan berikan
contoh untuk penjelasan anda !
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