Chemistry - Liquid Solution Question with Solution | TestHub

Let the number of moles of benzene be n_Aand that of toluene be n_B.

${\mathrm{n}}_{\mathrm{A}}+{\mathrm{n}}_{\mathrm{B}}=\frac{78}{78}+\frac{46}{92}=1+0.5$

${\mathrm{P}}_{\mathrm{A}}={\mathrm{P}}_{\mathrm{A}}^0{\mathrm{X}}_{\mathrm{A}}={\mathrm{P}}_{\mathrm{A}}^0 \left(\frac{{\mathrm{n}}_{\mathrm{A}}}{{\mathrm{n}}_{\mathrm{A}}+{\mathrm{n}}_{\mathrm{B}}}\right)$

${\mathrm{P}}_{\mathrm{A}}={\mathrm{P}}_{\mathrm{A}}^0\times \frac{1}{1.5}=\frac{75}{1.5}=50$

The partial vapour pressure (in torr) of benzene, at${20}^0\mathrm{C}$for a solution containing 78 g of benzene and 46 g of toulene, is 50 torr.