Activity Coefficients of Aqueous Solutions of NaOH and KOH in Wide Concentration and Temperature Ranges

Abstract

Up to now, there exist a quite wide temperature interval between 70 or 80 and 150 °C with no sufficiently reliable experimental data of mean activity coefficients for aqueous NaOH as well as KOH solutions. In order to fill this gap, it was tried to derive suitable correlation equations for this quantity in dependence on the molality (for NaOH in the range mNaOH = 2-25 mol kg-1, for KOH in the range mKOH = 2-18 mol kg-1) and temperature (in the range 0-200 °C for both kinds of solutions) on the basis of the available data of this quantity and with the use of the previously derived correlation equations for the water activity in aqueous solutions of NaOH and KOH under the same conditions. The comparison between the calculated and experimental data was discussed.