Under atmospheric conditions the acetone-chloroform azeotrope boils at \(64.6^{\circ} \mathrm{C}\) and contains 33.5 mole percent acetone. The vapour pressures of acetone and chloroform at this temperature are 995 and \(855 \mathrm{~mm} \mathrm{Hg}\) respectively. Calculate the composition of the vapour at this temperature in equilibrium with a liquid analyzing 11.1 mole percent acetone. We are given that van Laar equation

\[ \ln \gamma_{1}=\frac{A x_{2}^{2}}{\left(\frac{A}{B} x_{1}+x_{2}\right)^{2}} \quad \text { and } \quad \ln \gamma_{2}=\frac{B x_{1}^{2}}{\left(x_{1}+\frac{B}{A} x_{2}\right)^{2}} \]