TERNARY DIFFUSION IN THE SYSTEM CACL2-DEGREES-C(HCL+H2O AT 25)

Measurements of the four mutual diffusion coefficients of the ternary systems CaCl2(1) + HCl(2) + H2O using the diaphragm cell method are de scribed, T = 25 degrees C. The concentrations were c(1) = 0.5, 1, 1.5 M with c(2) = nc(1), n = 1, and c(1) = 0.5, 1 M with c(2) = 1.0 and 2. 0 M, n = 2. Density measurements were performed to transform the cell fixed diffusion coefficients to solvent fixed ones wherefore the parti al molar volumes are needed. By proper extrapolation of literature dat a we calculated the activity coefficients of both solutes to convert t he D'(ij) matrix into the matrix of the phenomenological coefficients Omega'(ij). The validity of the Onsager reciprocity relations was conf irmed within the limits of experimental error. We give a discussion of the remarkably high D'(21) value compared to D'(22) we found in our s ystems.