Variational thermodynamics calculation for entropy of mixing of molten alkali alloys

The entropy of mixing of NaCs, NaK and KRb liquid alloys as a function of composition is computed based on the hard sphere model using variational thermodynamics. The hard sphere diameters are determined which ensure minimum Helmholtz free energy for the system. It is found that irrespective of widely differing size factors these systems exhibit almost ideal entropy of mixing.