# At room temperature $25^{\large\circ}C$,the vapour pressure of pure methyl alcohol is 92 torr.Mol fraction of $CH_3OH$ in a solution in which vapour pressure of $CH_3OH$ is 24 torr at $25^{\large\circ}$ is ?

$\begin{array}{1 1}(a)\;0.40\\(b)\;0.50\\(c)\;0.26\\(d)\;0.80\end{array}$

$\large\frac{P^0-P}{P^0}$=mol fraction of solute
$\large\frac{92-24}{92}$$=0.74$
$\therefore$ mol fraction of $CH_3OH=1-0.74$
$\Rightarrow 0.26$
Hence (c) is the correct answer.