Question

Equal masses of ethane and hydrogen are mixed in an empty container at ${25}^{o}C$. The fraction of total pressure exerted by hydrogen is ___.

• A. $1:2$
• B. $1:1$
• C. $1:16$
• D. $15:16$

Answer 1

The correct option is D $15:16$

$p_{H_2}=X_{H_2}.p$
$p_{H_2}=\frac{w_{H_2}/M_{H_2}}{\frac{w_{H_2}}{M_{H_2}}+\frac{w_{C_2{H}_6}}{M_{C_2{H}_6}}}.p$
$p_{H_2}=\frac{a/2}{\left(a/2\right)+\left(a/30\right)}.p$
$p_{H_2}=\frac{a\times 30}{2\times 16a}.p$
$\frac{p_{H_2}}{p}=\frac{15}{16}$