Question

The partial pressure of hydrogen in a flask containing $2g$ of $H_2$ and $32g$ of $S{O}_2$ is :

• A. $\frac{1}{16}$ of total pressure
• B. $\frac{1}{2}$ of total pressure
• C. $\frac{2}{3}$ of total pressure
• D. $\frac{1}{8}$ of total pressure

Answer 1

The correct option is C $\frac{2}{3}$ of total pressure

The molar masses of $H_2$ and $S{O}_2$ are 2 $g/mol$ and 64 $g/mol$ respectively. The number of moles of hydrogen are $\frac{2}{2}=1mol$.

Total number of moles of $S{O}_2$ present are $\frac{32}{64}=0.5mol$.

The mole fraction of hydrogen is $\frac{1}{1+0.5}=\frac{2}{3}$

The ratio of the partial pressure of $H_2$ to the total pressure will be equal to its mole fraction $\frac{2}{3}$.

Hence, the partial pressure of hydrogen in a flask containing $2g$ of $H_2$ and $32g$ of $S{O}_2$ is $\frac{2}{3}$ of total pressure.