A green coloured hydrated metallic salt on heating loses its water of crystallisation molecules and gives a suffocating smell. Identify the salt and write the chemical equation.

Explanation

The salt is hydrated ferrous sulphate `(FeSO_(4) .7H_(2)O)`
The salt decomposes upon heating and forms the following products :
`FeSO_(4) underset("Green")(.7H_(2)O(s)) overset("heat (slow)")to FeSO_(4)(s) + 7H_(2)O(l)`
`2FeSO_(4)(s) overset("heat (strong)")to Fe_(2)O_(3)(s) + SO_(2) (g) + SO_(3)(g)`
Both the gases give suffocating smell.