Question

Equal masses of methane of oxygen are mixed in an empty container at ${25}^{o}C$. The fraction of the total pressure exerted by oxygen is:

• A. $1/2$
• B. $2/3$
• C. $\frac{1}{3}\times \frac{273}{298}$
• D. $1/3$

Answer 1

The correct option is D $1/3$

$\text{DALTON'S LAW OF PARTIAL PRESSURES}$:

The relation between the total pressure of a mixture of non-reacting gases and the pressures of the individual gases was expressed by Dalton in the form of law of partial pressures. The partial pressure of a gas in a mixture is defined as the pressure at which the gas would exist if it is allowed to occupy the whole volume of the mixture at the same temperature.
According to Dalton's law of partial pressures, the total pressure of a mixture of gases is equal to the sum of the partial pressures of the constituent gases.
$\frac{P_{O_2}^{\prime }}{P_T}=X_{O_2}=\frac{\frac{w}{32}}{\frac{w}{16}+\frac{w}{32}}=\frac{1}{3}$