Activity coefficients for the system HCl + BaCl2+ H2O at 298.15 K. Comparison of Scatchard's and Pitzer's interpretations

Abstract

Activity coefficients of hydrochloric acid in aqueous solutions of barium chloride have been measured at 298.15 K at constant total ionic strengths of 0.1, 0.5, 1.0, 2.0 and 3.0 mol kg^–1 using hydrogen–silver–silver chloride cells. The data were interpreted in terms of Scatchard's and Pitzer's equations whereupon it was found that, whereas the former gave a more accurate fit of the experimental results, the latter were nevertheless quite adequate and more convenient. Contrary to Harned and Gary's conclusions, hydrochloric acid follows Harned's rule equally well at all these ionic strengths, while quadratic terms are clearly warranted for barium chloride at I= 2.0 and 3.0 mol kg^–1.