Question 1 What are decomposition reactions?
Question 2 What happens when ferrous sulphate crystals are decomposed?
Question 3 What is electrolysis?
Question 4 What is photochemical decomposition. Give example?
Those reactions in which a compound split up into two or more simpler substances are called as decomposition reaction. They are carried out by applying heat, light, electricity.
CaCO3 (s) → CaO (s) + CO2 (g)
Limestone Heat (Quick lime)
When decomposition reaction is carried out by heating it is called thermal decomposition.
2FeSO4(s) → Fe2O3(s) + SO2(g) + SO3(g)
Ferrous Sulphate Ferric oxide Sulphur dioxide Sulphur trioxide
A smell of burning sulphur is obtained due to the formation of sulphur dioxide gas. When the decomposition is carried out by electricity, it is called electrolysis.
2H2O(l) → 2H2(g) + O2(g)
Water electricity decomposition Hydrogen Oxygen
2 Al2O3 (cryolite) → 4 Al (s) + 3 O2 (g)
When decomposition reaction is carried out by light it is called Photochemical decomposition.
2AgBr(s) → 2Ag(s) +Br2(g)
Light Yellow Sunlight Grey
2AgCl(s) → 2Ag(s) + Cl2(g)
2H202(l) → 2H20(l) + O2(g)
The digestion of food in our body is an example of decomposition reaction.