Analysis of Activity Coefficients in Aqueous Solutions of Alkali Metal Bromides Based on Dielectric Properties

Extended Debye-Huckel (EDH) theory was used to calculate activity coefficients in aqueous solutions of alkali-metal bromides at 298 K from experimentally determined values of their static permittivities. Calculations with non-optimized model parameters fit the nonmonotonic concentration-dependent trend of the activity coefficients and the cation radius-dependent trend of the activity coefficients. The latter is explained by hydration weakening and ion association strengthening in response to increasing cation radius in the salt series.

Automated summary

The study applied the Extended Debye-Huckel theory to calculate the activity coefficients of alkali-metal bromides in aqueous solutions at 298K based on experimentally determined static permittivity values. The calculations without optimized model parameters successfully captured the nonmonotonic concentration-dependent trend and the cation radius-dependent trend of the activity coefficients, which were attributed to the weakening of hydration and the strengthening of ion association as the cation radius increased in the salt series.