Question

40 mL of mixture of hydrogen and oxygen gases was placed in a gas burette at 48°C and 1 atm pressure. A spark was applied so that the formation of water is complete. The volume of the remaining hydrogen gas was 10 ml at 48°C and 1 atm pressure. Find the initial mole percentage of hydrogen in the mixture.

Answer 1

2H₂(g) + O₂(l) → 2H₂O(l)

Total initial vol. of H₂ and O₂ = 40 ml.

At const pressure and temperature conditions.

volume of remaining H₂ = 10 ml.

H₂ & O₂ react in 2 : 1 molar ratio

there for volume of H₂ reacted = 20 ml.

& vol. of O₂ reacted = 10 ml.