Abstract: Based on the interaction of all particles in solution,a mixture of ions and point dipoles as an electrolyte solution is proposed.The partition functions,Virial coefficient and internal energy are calculated by using cluster expansion method. It is found that the partition function can be expanded in cluster integrals whi ch are easily calculated without three body interaction.Related numerical resul ts have been given and discussed.

Key words: ion-dipole mixture, aqueous electrolyte solution, intern al energy, Virial coefficient, cluster expansion