(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 is green in colour. On heating, the green crystals are converted into a dirty-yellow anhydrous solid as it loses water of crystallization.

(b) When ferrous sulphate is strongly heated anhydrous material loses sulphur dioxide and sulphur trioxide leaving a reddish-brown iron oxide.
$2{\mathrm{FeSO}}_4\to {\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{SO}}_2+{\mathrm{SO}}_3$