Abstract: | A universal thermodynamic model of calculating the mass action concentrations of components in a ternary strong elec-trolyte aqueous solution has been developed based on the ion and molecule coexistence theory, and verified in the NaCl-KCl-H2Oternary system at 298.15 K, To compare the difference of the thermodynamic model in binary and ternary strong electrolyte aqueous solutions, the mass action concentrations of components in the NaCI-H20 binary strong electrolyte aqueous solution were also com-puted at 298.15K. A transformation coefficient was required to compare the calculated mass action concentration and reported activ-ity because they were obtained at different standard states and concentration units. The results show that the transformation coeffi-cients between calculated mass action concentrations and reported activities of the same components change in a very narrow range.The calculated mass action concentrations of components in the NaCl-H2O and NaCl-KCl-H2O systems are in good agreement with the reported activities. This indicates that the developed thermodynamic model can reflect the structural characteristics of solutions,and the mass action concentration also strictly follows the mass action law. |