1. Consider a liquid solution of species A and B at equilibrium with its vapor phase. The vapor is an ideal-gas mixture. The liquid phase, however, is non-ideal. The convention I activity coefficient of species A in the liquid is given by the following expression In (YA) = C x with C = 1.20 at T = 300 K. At T = 300 K, the vapor pressures of the pure species are p = 35 kPa and PB = 20 kPa. Pressure effects on the activity coefficients can be neglected. (a) (b) (c) (d) Use the Duhem-Margules equations to derive an expression for the convention I activity coefficient of species B in the liquid, YB, in terms of composition at T = 300 K. Consider a liquid solution of composition x = 0.25 at T = 300 K at equilibrium with its vapor phase. Find the vapor pressure of the liquid solution, p, and the composition of the vapor phase. The binary system has an azeotrope at T = 300 K. Calculate the vapor pressure, p, at the azeotrope and the composition. Sketch the pxy diagram of the binary at T = 300 K.