Question

Sulphuric acid on reaction with sodium sulphide results in the evolution of a gas X with rotten egg smell. Identify the gas X.

• A. Carbon monoxide
• B. Sulphur dioxide
• C. Nitrogen dioxide
• D. Hydrogen sulphide

Answer 1

The correct option is D Hydrogen sulphide

Sulphuric acid reacts with sodium sulphide to give sodium sulphate and hydrogen sulphide $\left(H_{2}S\right)$ gas.

$N{a}_{2}S\left(s\right)+H_{2}S{O}_4\left(aq\right)\to N{a}_{2}S{O}_4\left(aq\right)+H_{2}S\left(g\right)$

$H_{2}S$ gas is colourless, highly flammable and has a characterisitc rotten egg smell. When inhaled in large quantities, hydrogen sulphide causes headache to humans.