Question

A closed vessel contains a mixture of one mole of oxygen $\left(O_2\right)$ and two moles of Nitrogen $\left(N_2\right)$ at $300\text{K}$. Find the ratio of partial pressure exerted by $O_2$ to the total pressure exerted by mixture on the wall of vessel?

• A. $1:3$
• B. $3:1$
• C. $2:3$
• D. $1:2$

Answer 1

The correct option is A $1:3$

From Dalton's law of partial pressures,
$P_{\text{total}}=P_{O_2}+P_{N_2}$
We know,
$P_{\text{total}}V=n_{\text{total}}\times R\times T...\left(i\right)$
where, $n_{\text{total}}=n_{O_2}+n_{N_2}$
Also,
$P_{O_2}V=n_{O_2}RT....\left(ii\right)$

From equation $\left(i\right)$ and $\left(ii\right)$, we get
$\frac{P_{O_2}}{P_{\text{total}}}=\frac{n_{O_2}}{n_{O_2}+n_{N_L}}=\frac{1}{1+2}=\frac{1}{3}$