Solve part (A)

A pure liquid composed of species A is brought into contact with a stagnant gas which initially contains only species B. Evaporation of the liquid begins at !=0, leading to a mixture of A and B in the gas; B is insoluble in the liquid and therefore remains in the gas phase. The liquid interface is maintained at 2=0, and the gas occupies the space z>0. The mole fraction of A in the gas at z=0 is XA0. The system is at constant temperature and pressure and the gas mixture is ideal, so that the total molar concentration in the gas is constant, (a) Show that the mole fraction of A in the gas, A(z. t), is governed by ata - DAB + 1) ar *Odz * (2.0)=0, *(0,1)=240 * (1) *0