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

Mean activity coefficients (γ ± ), osmotic coefficients (φ), and excess Gibbs free energies ( G E ) 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 ), H 2 O(1 − w )|H + (glass membrane ISE) over the molality range from dilute solution to about 4 mol/kg in these mixed-solvent systems.