Theoretical considerations on single and mixed solvent electrolyte solutions

Electrolyte terms are considered to belong to a different framework (McMillan-Mayer) than the physical terms of the thermodynamic models (Lewis-Randall). The electrolyte terms should be converted to the framework of the physical model, prior to the combination of the physical and electrolyte terms. If the relative static permiitivity (RSP) of the solution (mixed or single) does not depend on the ionic concentration, then the two frameworks are equivalent for equations of state (EoS). For activity coefficient models (GE models), a pressure correction term is needed to consistently combine the electrolyte and the physical model. These corrections are more important for higher concentrations.