ON THE USE OF SEMIEMPIRICAL ELECTROLYTE THEORIES FOR THE MODELING OF SOLUTION CHEMICAL-DATA

In order to compare thermodynamic data on complex formation reactions, protolytic, redox sind solubility equilibria determined in ionic medi a of various types, it is necessery to refer them to a common standard state, usually with pure water as the solvent. This requires estimate s of the activivity coefficients of reactants and products. We have co mpared the Bronsted-Guggenheim-Scatchard specific ion interaction (SIT ) model and the Fitter models and shown that they for all practical pu rposes are equivalent, for the description of the ionic medium/ionic s trength dependence of concentration equilibrium constants for ionic st rengths up to 3 to 4 m. Equations relating the SIT specific ion intera ction coefficients epsilon(i,j) and the Pitzer parameters beta((0)) an d beta((1)) for ionic components, and Delta beta((0))and Delta beta((1 )), for reactions are presented.