3513
J. Phys. Chem. 1992, 96, 3513-3520
Thermodynamics of Multicomponent, Miscible, Ionic Solutions: Generalized Equations for Symmetrical Electrolytes Simon L. Clegg*vt and Kenneth S. Pitzer*,t School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, U.K..and Department of Chemistry, University of California, Berkeley, California 94720 (Received: June 13, 1991; In Final Form: November 5, 1991)
Model equations for the excess Gibbs energy and solvent and solute activity coefficients are developed for mixtures containing an indefinite number of ions of the same charge type, over the entire concentration range. The equations, expressed on a mole fraction basis, comprise an extended Debye-Huckel term which is a function of composition and a Margules expansion carried out to the four suffix level. Empirical parameters may be determined from data for solutions or molten salt mixtures containing no more than three ions. As an example, the model is applied to aqueous systems at 298.15 K containing the ions H+,Na+, K+,C1-, and NO
