For each component in a binary mixture, one could make a vapor–liquid equilibrium diagram. Such a diagram would graph liquid mole fraction on a horizontal axis and vapor mole fraction on a vertical axis. In such VLE diagrams, liquid mole fractions for components 1 and 2 can be represented as and respectively, and vapor mole fractions of the corresponding components are commonly represented as and . Similarly for binary mixtures in these VLE diagrams:
