Question

Equal weights of methane and oxygen are mixed in an empty container at ${25}^{\circ }C$ the fraction of the total pressure exerted by oxygen is:

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

Answer 1

The correct option is A $\frac{1}{3}$

The fraction of the total pressure exerted by oxygen = its mole fraction
$=\frac{n_{o_2}}{n_{o_2}+n_{C{H}_4}}=\frac{\frac{x}{32}}{\frac{x}{32}+\frac{x}{16}}=\frac{x}{32}\times \frac{32}{3x}=\frac{1}{3}$