The solubility of silver chloride in a mixed solvent from 15°C to 45°C (1940)
AuthorsDavis, D. J. O'Dshow all
The qualitative parallelism between the solubility of ionic crystals and the dielectric constant of the solvent medium has long been recognised and the more recent development of theories regarding the interaction between ions and solvent has lead to increasing use of solubility data for the estimation of ionic diameters and the degree of solvation of ions. A quantitative expression for this relation may be found from Born's equation, which gives the work of transfer of an ion, assumed spherical, carrying charge ziε, from a medium of dielectric constant D1‚ to a medium of dielectric constant D2‚ as [equation] where a1 is the ionic radius. This work of transfer can be equated to a free energy change, whose value [equation] Per ion, where f1‚ and f2‚ are the activity coefficients of the ion in the two media.