Question

A mixture of two immiscible liquids nitrobenzene and water boiling at ${99}^{o}C$ has a partial pressure of water 733 mm and of nitrobenzene 27 mm. The ratio of masses of water and nitrobenzene in mixture is :

Answer 1

The ideal gas equation is $PV=nRT=\frac{w}{M}RT$

Hence, $w=\frac{PVM}{RT}$

Hence, the ratio of the mass of water (w) to the mass of nitrobenzene (w') is $\frac{w}{w^{\prime }}=\frac{PM}{P^{\prime }{M}^{\prime }}=\frac{733\times 18}{27\times 123}\approx 4$.