Equal masses of Helium, methane and sulphur dioxide are taken in a closed container at 300 K . Partial pressure ratio of $\mathrm{He}:{\mathrm{CH}}_4:{\mathrm{SO}}_2$is

${\mathrm{W}}_{\mathrm{He}}:{\mathrm{W}}_{{\mathrm{CH}}_4}:{\mathrm{W}}_{{\mathrm{SO}}_2}=1:1:1$
${\mathrm{n}}_{\mathrm{He}}:{\mathrm{n}}_{{\mathrm{CH}}_4}:{\mathrm{n}}_{{\mathrm{SO}}_2}=\frac{1}{4}:\frac{1}{16}:\frac{1}{64}$
$$\begin{gathered} {\mathrm{n}}_{\mathrm{He}}:{\mathrm{n}}_{{\mathrm{CH}}_4}:{\mathrm{n}}_{{\mathrm{SO}}_2}=16:4:1; \\ \mathrm{pressure}\propto \mathrm{moles} \mathrm{at} \mathrm{constant} \mathrm{V} \mathrm{and} \mathrm{T}; \\ \mathrm{So} \mathrm{mole} \mathrm{ratio} \mathrm{is} \mathrm{pressure} \mathrm{ratio}; \end{gathered}$$