Effect of Attractive Solvent–Solvent and Solvent–Solute Interactions on Partial Molal Quantities

The effect of the perturbation due to attractive solute–solvent and solvent–solvent interactions on the partial molal volume (PMV), entropy (PME), and enthalpy in infinitely dilute solution has been formulated on the basis of the first-order perturbation theory which comes from the van der Waals picture of liquid. PMV is found to be composed of the two compensating factors which arise from the solute–solvent and solvent–solvent attractive interactions treated as the perturbation; when the former is larger than the latter PMV becomes smaller. PME is influenced only indirectly by the attractive perturbation through the volume change due to the perturbation interactions. The limitations of the basic expressions derived are discussed in the case of large solute.