Which of the following statements about the composition of the vapour over an ideal 1: 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at ${25}^{0}C$. (Given, vapour pressure data at ${25}^0\mathrm{C}$, benzene =12.8kPa, toluene =3.85 kPa

$\begin{array}{l}{\mathrm{p}}_{\text{Benzene }}={\mathrm{x}}_{\text{Benzene }}{\mathrm{p}}_{\text{Benzene }}°\\ {\mathrm{p}}_{\text{Toluene }}={\mathrm{x}}_{\text{Toluene }}{\mathrm{p}}_{\text{Toluene }}°\end{array}$

$\text{ For an ideal }1:1\text{ molar mixture of benzene and toluene, }$

$x_{\text{Benzene }}=\frac{1}{2} \text{ and }{x}_{\text{Toluene }}=\frac{1}{2}$

$p_{\text{Toluene }}=\frac{1}{2} p_{\text{Toluene }}°=\frac{1}{2}\times 3.85\mathrm{kPa}=1.925\mathrm{kPa}$

$p_{\text{Benzene }}=\frac{1}{2}{p}_{\text{Benzene }}°=\frac{1}{2}\times 12.8\mathrm{kPa}=6.4\mathrm{kPa}$

Thus, the vapour will contain a high percentage of benzene as the partial vapour pressure of benzene is higher as compared to that of toluene.