Volumetric Properties of Single Aqueous Electrolytes from Zero to Saturation Concentration at 298.15 °K Represented by Pitzer’s Ion-Interaction Equations

The ion interaction approach developed by Pitzer allows the prediction of various thermodynamic characteristics of multiple-solute electrolyte solutions, if the respective parameters for each type of single-solute electrolyte solution are known. The present paper discusses the Pitzer approach to the calculations of the volumetric properties of single-solute electrolyte solutions. The databases for the densities and the apparent molal volumes versus concentrations were created at 298.15 °K using essentially all published relevant data for each single-solute electrolyte solution. Poor experimental data were discarded by a statistical treatment applied to these databases. Proper treatment of all good quality density and apparent molal volume data, in a wide range of concentrations from infinite dilution through saturation, allowed us to evaluate the volumetric ion interaction parameters (V̄0MX, βMX(0)V, βMX(1)V, βMX(2)V, and CMXV) at 298.15 °K for 102 electrolytes. Strong linear relationships between the βMX(1)V, βMX(2)V, or CMXV, and βMX(0)V volumetric ion interaction parameters were observed for all analyzed solutes with slopes depending on the solute valency types.