ACTIVITY-COEFFICIENT MEASUREMENTS OF THE SYSTEM HCL-ZNCL2-H2O AT 25 AND 35-DEGREES-C

Electromotive force measurements were carried out on the HCl-ZnCl2-H2O system al constant total ionic strengths of 0.1, 0.2, 0.5, 1.0 and 2.0 mol-kg-1 at 25 and 35-degrees-C using a cell consisting of Pt, H2(g, 1 atm)\HCl(mA), ZnCl2(mB)\AgCl/Ag. The data were interpreted by the mixed electrolyte equations of Pitzer and K(im) in order to evaluate mixing ion-interaction parameters. The activity coefficients of ZnCl2 and the Gibbs excess free energies of mixing are calculated and presented at I = 2.0 mol-kg-1 and compared with similar systems containing transition metal chlorides.