Question

Equal weights of methane and oxygen are mixed in an empty container ${25}^{\circ }C$. 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 $\frac{1}{3}$

Let 32 $g$ of each gas be present.

Moles of $O_2=32/32=1$

Moles of $C{H}_4=\frac{32}{16}=2$

Mole fraction of $O_2=\frac{1}{1+2}=\frac{1}{3}$

which is the same as the fraction of pressure.

So, the correct option is $A$