Question

A gas that turns moist blue litmus red?

Answer 1

Carbon dioxide (${\mathrm{CO}}_2$ ) is the gas that turns moist blue litmus red. Litmus paper tests are given as follows-

• The acid turns litmus paper from blue to red.
• The base turns litmus paper from red to blue

Carbon dioxide (${\mathrm{CO}}_2$ ) gas is acidic in nature hence it turns blue litmus paper into red litmus paper.