Study of ion-solvent interactions in formamide + water mixtures by the measurement of viscosity of sodium chloride solutions

Abstract

The relative viscosity of NaCl solutions has been measured as a function of temperature and solvent composition in the formamide + water system. The resulting Jones–Dole B-coefficients are examined by considering each solvent mixture as an “averaged pure solvent” and applying transition state theory. B-coefficients and related parameters were found to be monotonic functions of solvent composition. Changes in viscosity are interpreted in terms of a reduction of structure breaking by the chloride ion and an increase in long-range ordering of solvent molecules by the ionic electric fields, as the solvent composition moves towards a higher proportion of formamide.