Solubility of AgCl in Molten NaCl ‐ AlCl3 and KCl ‐ AlCl3

Abstract

Measurements of solubility (in mol fraction units) in molten and were determined by an electromotive force technique. For the experiments, the temperature was maintained at 448 K and the composition of the solvent varied from . There was a compositional dependence of the solubilities with a minimum near the equimolar solvent composition. The minimum solubility in mol fraction of was at . The true solubility produce for at 448 K was calculated to be . The magnitude of the solubility product is primarily related to the fact that the standard free energy of formation of from and is about 67 kJ mol−1 more negative than the corresponding free energy for (i.e., is unstable). In basic and in somewhat acidic melts, the solubility is related to the formation of the associated ionic species such as ,, , and . From our measurements, the formation constant of at 448 K, , was . Further, the specific bond free energy for the associated complex , , has been calculated as −47.5 kJ mol−1. For the experiments, the composition was maintained at the equimolar and the temperature varied in the range 518 to 583 K. The solubility increases from at 518 K to at 583 K. The apparent heat of solution was 17.68 kJ mol−1 for this temperature range.