On the Krichevskii parameter of solutes in dilute solutions: Formal links between its magnitude, the solute-solvent intermolecular asymmetry, and the precise description of solution thermodynamics

Abstract

We present a novel approach for the calculation of the Krichevskii parameter AKr of solutes in dilute mixtures according to a universal thermodynamic expression that links the solute-solvent intermolecular asymmetry, as described by the Henry's law constant of the solute species in a pure solvent, to the desired AKr. The derived expression obeys two key thermodynamic constraints, i.e., corresponding to the behavior of either an ideal gas solute or a solute behaving as a solvent species representing a special case of Lewis-Randall ideal solution. Then, we provide a comparison between the thermodynamically consistent AKr values generated by this approach and those reported in the literature, from diverse experimental sources, and for a variety of aqueous solutes. Finally, we discuss how the AKr=0 line divides the P−T plane of the pure solvent into two regions characterized by unambiguous solute-solvent intermolecular asymmetries, and provide additional microscopic as well as macroscopic interpretations for AKr.