A vapor-phase mixture of components 1 and 2 is compressed at fixed temperature until the vapor completely condenses. The vapor contains 30 mol% component 1 and 70 mol% component 2. The saturation pressures for components 1 and 2 at the temperature of the system are 0.82 and 1.93 bar, respectively. The bubble pressure of a 50:50 mixture of components 1 and 2 is 1.08 bar.

a) Estimate the pressure require to completely liquify the 30:70 mixture, assuming that the excess Gibbs free energy of the liquid is well-modeled by the one-parameter Margules equation.

b) Would the required pressure to liquify the mixture be higher or lower if components 1 and 2 formed an ideal solution?