Question

Equal weights of $CH_{4}$ and $H_{2}$ are mixed in an empty container at $25^\circ C$. The fraction of the total pressure exerted by $H_{2}$ is

• A. $\frac{1}{9}$
• B. $\frac{1}{2}$
• C. $\frac{8}{9}$
• D. $\frac{16}{17}$

Answer 1

Answer: (C)

$\frac{8}{9}$

Answer 2

Ratio of number of moles of $CH _{4}$ and $H _{2}$ are
$CH _{4}: H _{2}= \frac{x}{16}: \frac{x}{2}$
$=1: 8$
Hence, partial pressure exerted by
$H _{2}=\frac{8}{1+8} \times p_{\text {total }}$
$=\frac{8}{9} \times p_{\text {total }}$