Limiting partial molar volumes of electrolytes in dimethylformamide–water mixtures at 298.15 K

Abstract

Partial molar volumes at infinite dilution, V^∞₂, are reported for some 1 : 1 electrolytes in dimethylformamide (DMF)–water mixtures covering the whole fraction range at 298.15 K. The results obtained show that the behaviour of V^∞₂ both for alkali-metal halides and for hydrophobic electrolytes is dependent on the added DMF. In the water-rich region, the alkali-metal halides exhibit small variations of V^∞₂, but two extrema, a minimum and a maximum, in the case of the hydrophobic electrolytes, are observed. In the DMF-rich region, a drastic decrease of V^∞₂ for all electrolytes is exhibited. The results are discussed on the basis of ion–solvent and solvent–solvent interactions.