Equilibrium Compositions as Functions of Pressure and Temperature

At the low pressure P, both components can exist as liquids in their pure state, wiA and Tg representing their boiling point temperatures the T-x-y curves in this case cover the whole composition range. Moving to higher pressures we notice that, at 2, as the composition of A increases we reach the critical point C, where y = x/, and that at the still higher pressure P3, two critical points are present the T-x-y curves do not cover the whole composition range any more. 

The practical implications of this behavior in terms of separating a mixture of A and B are apparent at Pj, pure A and B can be recovered at P2, only B and at P3, neither. 

Similar phase diagrams are obtained if we consider the effect of temperature on Ae P-x-y relationship of a binary mixture. 

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