Acid Base And salt

Acids•Acids are those chemical substance which have a sour taste.• The acids present in plant material and animal are called organic acids.

Ex- citric acid,lactic acid.• The acids prepared from the materials of the earth are called mineral acids.• Ex- hydrochloric acid,sulphuric acid.

• An acids which is completely ionized in water and thus produces a large amount of hydrogen ions is called a strong acid.• All the mineral acids are strong acids.Only one mineral

acid,carbonic acid is a weak acid.• Strong acids are very dangerous to drink• Even the dilute solutions of stong acids are extremely

harmful to drink.• Ex- HCL,H2SO4.

Strong Acids

• An acid which is partially ionized in water and thus produses a small amount of hydrogen ions is called a weak acid

• The organic acids are weak acid.• The dilute solution of weak acids are quite safe to drink.• The organic acids like acetic acid,citric acid and tartaric acid

are used as food ingredients.• Ex- acetic acid(in the form of vinegar) is used for making

pickles and tamato ketchup,cabonic acid is used in fizzy soft drink.CH3COOH, H2CO3

Weak acid

•A concentrated acid is one which contains the minimum possible amount of water in it.The concentrated of an acid is decreased by adding more water to it.When water is added to a concentrated acid,then a dilute acid is formed.Thus, a dilute acid is one which contains much more of water in it.

Concentrated and Dilute Acids

1. Acids are sour in Taste.2. Acids react with metals to produce

hydrogen gas 2HCl + 2Na 2NaCl + H23. Acids Conduct electricity.4. Acid turns blue timus to red.

Properties of Acids

5. Acid react with metal carbonate(and metal hydrogen carbonates) to form carbon dioxide gas Ex- NA2CO3 + 2HCL 2NaCL + CO2 + H2O6. Acids react with bases to form salt and water. Ex- NaOH + HCL NaCL + H207. Acids react with metal oxide to form salt and water. Ex-CuO + 2HCL CuCL2 + H2O8. Acids have corrosive nature.

Properties of Acids

Bases• Bases are those chemical substance which have a bitter taste.• Bases are chemical opposite of acids.• A base is a chemical substance which can neutralize an acid.• All the metal oxide and metal hydroxide are bases.• Ex- Ca(OH)2,NH4OH,Na2CO3, CaCO3

•A base which completely ionizes in water and thus produces a large amount of hydroxide ions is called a strong base.

Strong Bases

Weak Bases•A base which completely ionised in water and thus produces a small amount of hydroxide ions is called a weak base.

1. Bases have bitter taste.2. Bases feel soapy to touch.3. Bases turn red litmus to blue.4. Bases conduct electricity in solution(They are

electrolytes).5. Bases react with non-metal oxides to form salt

and water.

Properties of Bases

6. Bases conduct electricity in solutions(They are electrolytes) Ex-2NaOH (aq) + Zn (s) Heat Na2ZnO2 + H2 (g) 7. Bases react with acids to form salt and water. ex- 2NAOH (aq) + H2SO4 (aq) Na2SO4 (aq) + 2H2O (I) Sodium hydroxide sulphuric acid sodium sulphate water (base) (acid) (salt)

Properties of Bases

1. Sodium hydroxide uses in the manufacture of soap, paper and a synthetic fiber called ‘rayon’.

2. Sodium carbonate is used as washing soda and for softening hard water.3.Sodium hydroxide is used as baking soda in cooking food, for making baking soda.

Uses of Bases

• The strength of an acid or base is measured on a scale of number called pH scale.• The pH scale has value from 0 to 14.pH is a pure number, it has no unit. According to the rule of pH scale.• Neural substance have a pH of exactly 7.• Acids(or acidic solution) have a pH of less than 7.• Bases(or basic solution) have pH of more than 7.

Strength of acid and base solution:pH scale

• The common indicator(like litmus) can tell us whether the given substance is an acid or a base .They cannot tell us whether the given substance is a strong acid, a weak acid, strong base or a weak base. In other words, the common indicator cannot tell us the relative strength of acids or bases.• To obtain an idea of how acidic or basic a substance is,

universal indicator is used.• Universal indicator is mixture of many different

indicator(or dyes) which gives different colours at different pH value of the entire pH scale.

Universal Indicator

• A salt is a compound formed from an acid by the replacement of the hydrogen in the acid by a metal.• Salt is a general name and it does not refer only to sodium chloride.• Salt are formed when acid react with bases.• Ex- NaCL, ZnCL2, k2so4, CaSO4.

Salt

1. They form crystals when in solid form .2. They usually have a higher hardness because of their ionic bonding.3. An acid plus a base yields a salt and water.

HCl + NaOH NaCl + HOHor HCl + NaOH NaCl + H2O

Properties of Salts

1. A reaction between an acid and base.2. The products of a neutralization reaction are a salt and water.

Neutralization

pH Scale

1. 1.The pH scale gives a measure of the concentration of positive hydrogen ions in a solution.

2. A way of describing the acidic or basic strength of a solution.

3. The acidity of a solution can be expressed by using the pH scale.

The pH Scale

4.The scale ranges from 0 to 14.5.Acids range from 0 to 7, with 0 being the strongest acid.6.Bases range from 7 to 14, with 14 being the strongest base.7.Pure water, which is neither acid nor base, has a pH level of 7 or is neutral.

The pH Scale

Thank You Made By

Devanshu Sharma 10th A