Roasting of sulphides gives the gas X as a by product. This is a colourless gas with choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic, acts as a reducing agent and its acid has never been isolated. The gas X is

Options

A. `CO_2`
B. `SO_3`
C. `H_2 S`
D. `SO_2`

Answer

D

Explanation

Roasting of sulphides produces `SO_2`
` 2 Zn S + 3 O_2 to2 Zn O + 2SO_2`
(X )
` 2 SO_2 + 2 H_2 O + O_2 to 2 H_2 SO_4` ( acid rain)
` SO_2 + H_2 O to underset("sulphurousacid")(H_2SO_3)`
Sulphurous acid acts as a reducing agent. Being unstable it has never been isolated.