What is a decomposition reaction? Give an example of a decomposition reaction. Describe an activity to illustrate such a reaction by heating.
Decomposition reaction is a chemical reaction in which a single compound breaks down to simpler products. It is the opposite of combination reaction.
Example: Decomposition of ferrous sulphate crystals.
2FeSO4 (s) → Fe2O3 (s) + SO2 (g) + SO3 (g)
Heat the ferrous sulphate crystals; the colour of ferrous sulphate crystals is green. On heating, the ferrous sulphate crystals lose their water molecules and therefore the colour of the crystals changes. It is a decomposition reaction because they decompose to simpler molecules.