(a) What is the colour of ferrous sulphate crystals? How does this colour change after heating?
(b) Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?

(a) The colour of ferrous sulphate crystal is green. After heating, the ferrous sulphate crystal loses water molecules and forms anhydrous ferrous sulphate, which is white in colour. Subsequently, it decomposes to give ferric oxide, which is brown in colour, sulphur dioxide and sulphur trioxide.

(b) The products formed are ferric oxide, sulphur dioxide and sulphur trioxide. During this change, decomposition reaction occurs.

The chemical reaction is given as follows:

2FeSO₄ (s) → Fe₂O₃ (s) + SO₂ (g) + SO₃ (g)