The concepts of Gibbsian and non-Gibbsian, Lewisian and non-Lewisian thermo
dynamic variables are explored with respect to the thermodynamic properties
of liquid mixtures and solutions. The general structures of equations for
isochoric heat capacities, isentropic compressions and isentropic expansion
s are compared and contrasted. A simple rule is proposed for transcribing n
on-Gibbsian equations in terms of non-Lewisian partial molar properties. Th
e bases of equations for partial molar isochoric heat capacities, isentropi
c compressions and isentropic expansions are examined for (i) components of
liquid mixtures, and (ii) solute and solvent in solutions together with th
e properties of solutes at infinite dilution.