Studies in ion solvation in non-aqueous solvents and their aqueous mixtures. Part IX. The methanol–water system: further discussion of the ‘acid–base’ theory of ionic solvation; the ‘non-electrolytic’ effect

Abstract

Consideration of the molar free energies of transfer, ΔG_t°, of H⁺Cl^–, H⁺Br^–, and H⁺l^– and Li⁺Cl^–, Na⁺Cl^–, and K⁺Cl^–, from water to methanol–water mixtures containing 20·22, 33·40, 50, 68·33, and 90%(w/w) of methanol, confirms that the semiquantitative approach applied to transfers to 10% and 43·12% mixtures earlier in the Series holds across the whole range of composition, and affords further support for the ‘acid–base’ theory of ionic solvation in these systems. Comparison of ΔG_t° values for the halogen acids with those for Group O gases, and other evidence, suggests that a ‘non-electrolytic’ interaction makes a particularly important contribution to ΔG_t° for the iodide ion. New values of ΔG_t° for Rb⁺Cl^–, and Cs⁺Cl^–, for certain transfers, are presented and discussed.