Solvation thermodynamics of water in aqueous solutions. III. Ionic solutions

The solvation process of water in aqueous solutions of some simple electrolytes is studied. It is found that electrolytes at high concentrations cause the solvation free energy of water to be more negative than in pure liquid water. The initial effect, at very low concentrations, varies markedly from one electrolyte to another. The general trend is that increasing the size of the ions makes the effect of the solute on the solvation free energy of water more positive. Some tentative calculations of the effect of solutes on the entropies and the enthalpies of solvation of water are also presented.