Calculate the relative density of chlorine from hydrogen and air.

The relative density of gases is the ratio of their relative molecular weights.
Chlorine is a gaseous halogen, therefore its formula is Cl2
1. The relative density of chlorine for hydrogen – DH2 = Mr (Cl2) / Mr (H2); Mr (Cl2) = 35.5 x 2 = 71,
Mr (H2) = 1 x 2 = 2, so DH2 = 71/2 = 35.5
2. The relative density of chlorine in air – Dair = Mr (Cl2) / Mr (air), The relative molecular mass of air is approximately 29 (this is the average value, since air is a mixture of gases)
Dair = 71/29 = 2.4