The ratio between the volumes occupied by 4.4 grams of carbon dioxide and 2 grams of hydrogen gas is:

1 : 10

Reason —

Molar mass of CO₂ = 12 + 2 x 16 = 44 g/mole

∴ Moles of 4.4g CO₂ = 0.1

Molar mass of H₂ = 2 x 1 = 2 g/mole

∴ Moles of 2g H₂ = 1

Under the same conditions of temperature and pressure, the volume of a gas is directly proportional to the number of moles. Therefore, the volume ratio will be the same as the mole ratio.

Volume ratio = $\frac{\text{Vol. of CO}_2}{\text{Vol. of H}_2}$ = $\frac{0.1}{1}$ = 1 : 10