(a) What is the colour of ferrous sulphate crystals? How does this colour change after heating?

(b) Name the products formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change? Write chemical equation of the reaction.

(a) Ferrous sulphate crystals are light green in colour and contain water molecules (FeSO₄. 7H₂O). On heating, ferrous sulphate crystals lose water molecules and form white anhydrous ferrous sulphate (FeSO₄). On strongly heating, it becomes brown ferric oxide.

(b) The products formed on strongly heating ferrous sulphate crystals are ferric oxide, sulphur dioxide and sulphur trioxide.

This is a type of decomposition reaction (thermal decomposition).

The chemical equation for the reaction is given below:

$FeSO_4.7H_2O (s) \rightarrow FeSO_4 + 7H_2O$

$2FeSO_4 (s) \rightarrow Fe_2O_3(s) + SO_2(g) + SO_3(g) $