Thermodynamic Properties of Associated Solutions II. Mixtures of the Type A + B + AB_j

The theory of ideal associated solutions of the type A + B + AB_j is investigated. Equations describing the chemical equilibrium, number average molecular weight, activity coefficients and excess thermodynamic functions are given. For the type of association considered, G^E is always negative, H^E has the same sign as the standard enthalpy of the association reaction, ΔH°, and S^E can have positive or negative values. The excess entropy of mixing as a function of composition has a fairly complicated shape, especially in the region where the enthalpy and the free energy term compensate for each other. The extremum properties of the thermodynamic functions are at the stoichiometric mole fraction × = 1/(1 + j), and the functions have an asymmetric parabola‐like form.