# The vapour pressure of n-hexane and n-heptane are 46 and 13mm Hg.If the vapour pressure of a solution of these two liquids is 38mmHg,the mole fraction of n-hexane in solution is

$\begin{array}{1 1}0.24\\0.56\\0.66\\0.76\end{array}$

$38=x(46)+(1-x)13$
$\Rightarrow x=(38-13)/(46-13)=25/33=0.76$