Question

The hydrogen gas formed in a chemical reaction is collected over water at 30.0 ∘c at a total pressure of 734 mmhg . part a what is the partial pressure of the hydrogen gas collected in this way?

Answer 1

Answer: 702.2 mmHg

Explanation: According to Dalton's law of partial pressure, the total pressure is the sum of partial pressures of individual components.

$P=pH_2O+pH_2$

P=total pressure

$pH_2O$= partial pressure of water

$pH_2$ = partial pressure of hydrogen

partial pressure of $H_2O$ at 30°C is 31.8 mmHg

734 mmHg = 31.8 mmHg + $pH_2$

$pH_2$ = 702.2 mmHg

Answer 2

At a temperature of 30 deg C, the vapour pressure of water H2O is about 32 mm Hg. Therefore at a total pressure f 734 mm Hg, the partial pressure of the Hydrogen gas collected is:

P Hydrogen = 734 mm Hg – 32 mm Hg = 702 mm Hg