Thermodynamics of Electrolyte Solutions. Activity Coefficients of NaCl in NaCl-CoCh-H20 System at 25, 35 and 45°

Department of Chemistry, Osmania University, Hyderabad-600 007

Manuscript received 28th February 1989, accepted 4 May 1989

Activity coefficients for NaCI in the system NaCl-CoCl₂-H₂O at 25,35 and 45^o and at constant total ionic strengths have been measured by an e.m.f. method using  Na-ion selective electrode and silver- silver chloride reference electrode. The Harned coefficients were calculated at all the temperatures studied. The data at 25^o have been treated using the Pitzer equations for mixed e ctrolyte solutions and the corresponding binary and ternary Interaction parameters estimated. The excess free energies and osmoti oefficients of the system were calculated at 25• using these binary and ternary Interaction parameters.