What is a decomposition reaction? Give 2 examples each of decomposition taking placedue to heat, light and electricity

A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions often involve an energy source such as heat, light, or electricity to break the bonds of the compound.

Decomposition reactions can be represented by the general equation: AB → A + B

Examples of decomposition reactions due to heat (Thermal Decomposition):

1. The decomposition of calcium carbonate: When heated, calcium carbonate decomposes into calcium oxide and carbon dioxide. This reaction is used in the manufacture of lime.

   CaCO3 (s) → CaO (s) + CO2 (g)

2. The decomposition of potassium chlorate: When heated, potassium chlorate decomposes into potassium chloride and oxygen. This reaction is used in the preparation of oxygen.

   2KClO3 (s) → 2KCl (s) + 3O2 (g)

Examples of decomposition reactions due to light (Photodecomposition):

1. The decomposition of silver chloride: When exposed to light, silver chloride decomposes into silver and chlorine. This reaction is used in black and white photography.

   2AgCl (s) → 2Ag (s) + Cl2 (g)

2. The decomposition of hydrogen peroxide: When exposed to light, hydrogen peroxide decomposes into water and oxygen.

   2H2O2 (l) → 2H2O (l) + O2 (g)

Examples of decomposition reactions due to electricity (Electrolysis):

1. The decomposition of water: When an electric current is passed through water, it decomposes into hydrogen and oxygen. This reaction is used in the industrial production of hydrogen and oxygen.

   2H2O (l) → 2H2 (g) + O2 (g)

2. The decomposition of sodium chloride: When an electric current is passed through molten sodium chloride, it decomposes into sodium and chlorine. This reaction is used in the industrial production of sodium and chlorine.

   2NaCl (l) → 2Na (s) + Cl2 (g)