EMF STUDIES OF SILVER-NITRATE POTASSIUM-NITRATE MELTS

The activity coefficients of silver nitrate in binary melts of AgNO3-KNO3 were determined by emf measurements in a formation cell consisting of a silver and a nitrate electrode, in a temperature range of 513-583 K and in the concentration range allowed by the melting point of the mixture. Using a polynomial expression of the excess chemical potential, the excess Gibbs function and the characteristic constants of the investigated binary molten salt system were calculated. The excess molar entropy was calculated by combining the excess Gibbs function with calorimetric data on the excess enthalpy of mixing from the literature. The excess chemical functions were represented by orthogonal series involving Legendre polynomials, which enabled a comparison of the characteristic constants for different binary molten salt systems. The conformal ionic solution theory has been tested with respect to its capability to predict the excess chemical potentials of a binary additive system.