JEE Main 2007 — States of Matter Question with Solution

Let the mass of methane and oxygen is $w$ $\begin{aligned} & \text { mole fraction of oxygen }=\frac{\frac{w}{32}}{\frac{w}{32}+\frac{w}{16}} \\ & =\frac{\frac{1}{32}}{\frac{1}{32}+\frac{1}{16}}=\frac{\frac{1}{32}}{\frac{3}{32}}=\frac{1}{3} \end{aligned}$ Let the total pressure be $\mathrm{P}$ The pressure exerted by oxygen (partial pressure) $={\mathrm{X}}_{{\mathrm{O}}_2}\times {\mathrm{P}}_{\text{total }}$ $\Rightarrow \mathrm{P}\times \frac{1}{3}$ Hence, (C) is correct.