Question

A pale green salt x when heated turns reddish brown and emits gasses that smell of burning sulphur

Answer 1

 Salt --> FeSO4.7H2O

Reaction --> FeSO4.7H2O ---> (heat)  FeSO4 (s)  + 7H2O (g)

2FeSO4-->(heat)  -> Fe2O3 (s)  + SO2(g) + SO3(g)

SO2 gas has a  smell of burning sulphur.

Cheers

Best of Luck

Answer 2

this probably might be the answer.