Mean Activity Coefficients of KBr in the KBr–K2SO4–H2O Ternary System at 298.15 K by an Electromotive Force Method

Abstract

The mean activity coefficients of KBr in the KBr–K2SO4–H2O ternary system were determined at the total ionic strength ranging from (0.0100 to 3.0000) mol·kg–1 at 298.15 K by the electromotive force (EMF) method from the battery cell without a liquid junction: K-ISE|KBr(m1), K2SO4(m2)|Br-ISE. The mean activity coefficients of KBr were compared with those different ionic strength fractions yB of K2SO4 with yB = (0.8, 0.6, 0.4, 0.2, and 0). The experimental results showed that K-ISE and Br-ISE in this work had a good Nernst response, and the mean activity coefficients of KBr were fitted to the Pitzer models. Pitzer ion interaction parameters of θBr–·SO42– and φK+·Br–·SO42– which had not been reported were evaluated from present measurements of the mean activity coefficients of KBr.