Relationship between Coefficients of Activity and Dielectric Constants in Aqueous Solutions of Alkali Metal Fluorides

Coefficients of activity of alkali metal fluorides at 298 K in aqueous solutions are calculated according to the generalized Debye–Hückel theory using experimental values of the static dielectric constant of solutions. It is shown that calculations without optimized model parameters reproduce the nonmonotonic concentration dependence of the coefficients of activity. The dependence of the coefficients of activity on the radius of a cation is explained by the weakening of ionic association as the radius grows.