Question

Equal weighs of $C{H}_4$ and $H_2$ are mixed in a container at ${25}^o$C. Fraction of total pressure exerted by methane is?

Answer 1

Let the weight of $C{H}_4$ and $H_2$ be in

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

Moles of $H_2=\frac{M}{2}$

Total moles $=\frac{M}{16}+\frac{M}{2}=\frac{9M}{16}$

According to Dalton's law,

$P_{C{H}_4}=X_{C{H}_4}\times P_T$

Where,

$P_{C{H}_4}=$ Pressure exerted by $C{H}_4$

$X_{C{H}_4}=$ Moles fraction of $C{H}_4$

$P_T=$ Total Pressure

$X_{C{H}_4}=\frac{M/16}{9M/16}=\frac{1}{9}$

$\therefore$ Fraction of $P_T$ exerted by $C{H}_4$ is $\frac{1}{9}$