Vapor-Liquid Equilibrium Diagram for Non-Ideal Mixtures
This Demonstration shows P-x-y and T-x-y diagrams for vapor-liquid equilibrium (VLE) of a benzene/ethanol mixture. This liquid mixture is non-ideal, and the system has an azeotrope (a condition where liquid and vapor have the same composition).  The blue curve represents the liquid-phase boundary (bubble point), and the green curve represents the vapor-phase boundary (dew point). You can vary the temperature for the P-x-y diagram. Click and drag the black dot to change the benzene mole fraction and the temperature or pressure. The bar chart shows the moles of liquid (blue) and vapor (green) in equilibrium and the mole fraction of benzene in each phase (xB for liquid phase, yB for vapor phase). The system contains a total of 1 mol. The activity coefficients used in the modified Raoult's law are calculated using the two-parameter Margules model.

Download the CDF file to view the simulation using the free Wolfram CDF player.