The ternary and quaternary electrolyte systems: Activity coefficient of NaCl measured and modeled for NaCl + C2H5OH + H2O and NaCl + KCl + C2H5OH + H2O systems

• The ternary and quaternary electrolyte systems were measured and modeled by a galvanic cell.
• Using different molal salt ratio in mixed solvent with different ethanol mass fractions in water.

This work purpose is measuring and modeling of the ternary and quaternary systems consist of NaCl and mixed NaCl+KCl electrolyte in mixed solvents with different mass fractions (x) of C2H5OH in H2O, where x = 0.10, 0.20, 0.30, 0.40, and 0.50 and in the molality range of (0.0005–3.0) mol kg−1. Based on potentiometric measurement technique, the experimental data are obtained. A cell consists of a Na+-glass membrane and Ag/AgCl electrodes and series of electrolyte solutions, used to calculate the activity coefficients at (298.15 ± 0.05) K. The quaternary system of mixed NaCl + KCl electrolyte in mixed C2H5OH + H2O solvents is investigated by different molal salt ratios r (r = mNaCl/mKCl = 100, 150, 200 and 250). Modeling is implemented by using particularly, the Pitzer (P) and modified Pitzer by Merida et al. (MP) equations. There is a good agreement between the results obtained from both models. The modified Pitzer approach by Merida et al. permitted the determination of various binary ion-solvent and ternary ion-ion-solvent interaction coefficients which represents complementary data to the usual Pitzer interaction parameters for modeling the named electrolyte systems.