Question

Zinc reacts with aqueous sulfuric acid to form hydrogen gas:

      Zn (s) + H₂SO₄ (aq) → H₂ (g) + ZnCl₂ (aq)

In an experiment, 201 mL of wet H₂ is collected over water at 27 °C and a barometric pressure of 732.78 torr. The vapor pressure of water at 27 °C is 26.74 torr. The partial pressure of hydrogen in this experiment is __________ atm.

Answer 1

Solution :-

total barometric pressure = 732.78 torr

vapor pressure of water = 26.74 torr

partial pressure of the H2 gas = ?

total pressure = vapor pressure of water + partial pressure of the H2 gas

therefore

partial pressure of H2 gas = total pressure - vapor pressure of water

                                     = 732.78 torr - 26.74 torr

                                     = 706.04 torr

now lets convert this partial pressure of H2 gas from torr to atmosphere

706.04 torr * 1 atm /760 torr = 0.92900 atm

therefore partial pressure of the H2 gas = 0.92900 atm