What is an Acid?
Acids are sour in taste, turn blue litmus red, and dissolve in water to release H+ ions.
Example: Sulphuric acid (H2SO4), Acetic Acid (CH3COOH), Nitric Acid (HNO3) etc.
Properties of Acids:
- Acids have a sour taste.
- Turns blue litmus red.
- Acid solution conducts electricity.
- Release H+ ions in an aqueous solution.
Types of Acids:
Acids are divided into two types on the basis of their occurrence i.e., Natural acids and Mineral acids.
(i) Natural Acids:
Acids that are obtained from natural sources are called Natural Acids or Organic Acids.
Examples:
Methanoic acid (HCOOH)
Acetic acid (CH3COOH)
Oxalic acid (C2H2O4) etc.
Organic Acids and their Sources | |
Acids | Sources |
Acetic acid | Vinegar |
Ascorbic acid | Guava, amla |
Citric acid | Lemon, orange and other citrus fruits |
Lactic acid | Sour milk, curd |
Methanoic acid | Ant sting, nettle sting |
Oxalic acid | Tomato |
Tartaric acid | Tamarind |
(ii) Mineral Acids: Acids that are prepared from minerals are known as Mineral Acids Example; Inorganic acids, man-made acids or synthetic acid are also known as Mineral Acids.
Example:
Hydrochloric acid (HCl)
Sulphuric acid (H2SO4)
Nitric acid (HNO3)
Carbonic acid (H2CO3)
Phosphoric acid (H3PO4) etc.
Chemical Properties of Acid:
(i) Reaction of acids with metal: Acids give hydrogen gas along with respective salt when they react with a metal.
Metal + Acid → Salt + Hydrogen
Examples:
Hydrogen gas and zinc chloride are formed when hydrochloric acid reacts with zinc metal.

(ii) Reaction of acids with metal carbonate: Acids give carbon dioxide gas and respective salts along with water when they react with metal carbonates.
Metal carbonate + Acid → Salt + Carbon dioxide + Water
Examples:
Hydrochloric acid gives carbon dioxide gas, sodium chloride along with water when reacts with sodium carbonate.

iii) Reaction of acid with hydrogen carbonates (bicarbonates): Acids give carbon dioxide gas, respective salt and water when they react with metal hydrogen carbonate.
Acid + Metal hydrogen carbonate → Salt + Carbon dioxide + Water
Example:
Sulphuric acid gives sodium sulphate, Carbon dioxide gas and water when it reacts with sodium bicarbonate.
