When you reacted the zinc with the hydrochloric acid, you collected the hydrogen gas by water displacement. If the pressure in the room were 735 mm Hg, and the partial pressure of the water were 22 mm Hg, what would be the partial pressure of the hydrogen gas?

713mmHg

Explanation:

By using Dalton's law of partial pressure, the pressure outside the gas container is equal to the pressure inside it and this pressure equals the sum of the pressures of water and the gas.

i. e, P (total) = P (gas) + P (water)

P (gas) = P (total) - P (water)

P (gas) = 735 - 22

P (gas) = 713mmHg