Question

Fixed air = CO2:: VITIATED GAS =?

Answer 1

Answer:

Fixed air=CO2:: Vitiated gas =Air.

Answer 2

Vitiated GAS $=O_{2}.$

Explanation:

Carbon dioxide  ($CO_{2}$) is a colorless gas with a density 60%(approx.) higher than dry air. Carbon dioxide consists of a carbon atom covalently double bonded with two oxygen atoms.

Similarly,

Air($O_{2}$)  has been rendered impure by the breath of workers and horses, or by being mixed with the various gases given off in mines. It is frequently called return air.

Hence, Vitiated GAS $=O_{2}.$