Question

a green salt in heating decomposes it produce a colorless suffocating gas and leaves behind a brown residue . Name the salt and write decomposition reaction

Answer 1

That salt was iron sulphate. Iron sulphate(FeSO₄) produces a colourless suffocating gas and leaves behind a brown residue.

FeSO₄ (s) ⇒ Fe₂O₃ (s)  +  SO₂ (g) +  SO₃(g)
(green)            (brown)

hope it helps..:)

Answer 2

Answer: 1. The salt is ferrous sulphate $(FeSO_4)$

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

Explanation:

Decomposition reaction is a reaction in which one reactant forms two or more than two products on absorption of energy.

Ferrous sulphate which is green in color undergoes decomposition, that is it breaks into two or more than two products on absorption of energy. Two gases are evolved namely sulphur dioxide  and sulphur trioxide  and a solid ferric oxide which is brown in colour remains as such and is called as residue.

The balanced chemical equation representing the decomposition is:

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