Modeling of thermodynamic properties of multi-component electrolyte solutions

An empiric equation, G(H2O)(ex)/(1 - x(H(2)O))(2)= alpha + beta .x(H(2)O)/ln(x-(H(2)O)), representing the relation between the excess free energy G(H2O)(ex) and mole fraction of water x (H(2)O) in binary electrolyte solution, was developed and the parameters a and p in the equation were determined by fitting the experimental data for some binary aqueous systems of electrolytes such as CuCl(2), NiCl(2), HCl, NaCl, KCl, CaCl(2) and RaCl(2). The activities of water in such ternary and multi-component systems composed of 7 binaries as HCl - H(2)O - CuCl(2), HCl - H(2)O - NiCl(2), HCl - H(2)O - NaCl, NaCl H(2)O- KCl, NaCl(-) H(2)O- CaCl(2), KCl(-) H(2)O- CaCl(2), NaCl- H(2)O- BaCl(2), KCl- H(2)O- CaCl(2) and NaCl- H(2)O- KCl-BaCl(2) were predicted by a simplified sub-regular solution model developed by authors from the corresponding binary systems. The predicted results are in good agreement with the measured ones.