Effect of Cadmium Chloride and Ammonium Chloride Salts on the Enthalpy of Mixing of Pyridine + Water at 303.15 K

In this work, the effect of two dissolved inorganic salts (cadmium chloride, CdCl 2; ammonium chloride, NH 4 Cl) on the enthalpy of mixing ( H E ) of the pyridine + water binary system measured at 303.15 K using an isothermal displacement calorimeter with vapor space is investigated. Compared with the salt-free system, the addition (0.05 mass fraction) of the salts altered the magnitude of H E values to some extent depending on the mole fraction of x 1 . The importance of the solute–solvent and solvent–solvent interactions was demonstrated from the increasing exothermic H E values with increasing salt concentration (0.10 mass fraction). The experimental values of H E were fitted into the Redlich–Kister polynomial, and the adjustable parameters obtained by the least-squares method are reported.