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 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 which are obtained from natural sources are called Natural Acids or Organic Acids.
Examples:
Methanoic acid (HCOOH)
Acetic acid (CH3COOH)
Oxalic acid (C2H2O4) etc.
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 |
Maleic Acid | Apple |
(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:
- Reaction of acids with metal:
Acids give hydrogen gas along with respective salt when they react with a metal.
Metal + Acid → Salt + Hydrogen
- 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
- 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
Strong Acids
An acid which is completely ionised in water and produces (H†) is called Strong Acid.
Examples: Hydrochloric acid (HCl), Sulphuric acid (H2SO4), Nitric acid (HNO3)
Weak Acids
An acid which is partially ionised in water and thus produces a small amount of hydrogen ions (H†) is called a Weak Acid.
Example: Acetic acid (CH3COOH), Carbonic acid (H2CO3)
