Determination of Activity Coefficients, Osmotic Coefficients, and Excess Gibbs Free Energies of HCl in N,N-Dimethylformamide−Water Mixed Solvent Systems by Potentiometric Measurements

Abstract

Mean activity coefficients (γ±), osmotic coefficients (φ), and excess Gibbs free energies (GE) of HCl in mixed-solvent systems containing (0, 0.1, 0.2, 0.3, and 0.4) mass fractions (w) of N,N-dimethylformamide (DMF) in water were determined at 25 °C using the Pitzer ion-interaction model. These parameters were obtained from the experimental potentiometric data of the galvanic cell Ag|AgCl|HCl(m), DMF(w), H2O(1 − w)|H+(glass membrane ISE) over the molality range from dilute solution to about 4 mol/kg in these mixed-solvent systems.