Viscosities of binary liquid mixtures

Eyring deduced a relationship between viscosity and molar volume of a pure liquid on theoretical considerations. Katti and Chaudhri assumed that the molar free energy of activation of flow of a mixture is an additive property and derived an equation correlating viscosity of an ideal mixture with molar volumes and composition. This expression was further modified for non-ideal mixtures by introducing a work function to represent the deviation from ideal behaviour. The validity of this equation was examined using binary mixtures in which intramolecular and intermolecular interactions are present. It is concluded that this equation is not applicable to binary mixtures of components which exhibit self-association.