Ionic Hydration in an Aqueous Electrolyte Solution and Its Parameter

Abstract

Abstract Tait’s equation for water and Harned and Owen’s treatment of an electrolyte solution, together with sound velocity data, enabled the calculation of the molar volume of electrolytes in the solution state. The results agreed fairly well with the molar volume of the super-cooled molten electrolyte extrapolated to room temperature. The concentration coefficient of electrostrictive pressure, L=Pe/C1C2, the volume contraction due to the dissolution of one mole of solute, ΔV, and the volume of hydration water per mole of solute, Vh, as an incompressible part of water have been evaluated. We have found a common variable, [h], for L, ΔV and Vh, and it has been proposed that this variable can be used as a parameter of hydration expressing the mole number of hydration water per mole of electrolyte. A conventional hydration number, [h*], was also proposed.