Activity coefficients of hydrochloric acid and ionic interactions in the system HCl?CsCl?H2O from 5 to 50�C

Abstract

The activity coefficient of HCl (γA) in aqueous mixtures of HCl and LiCl was determined by emf measurements of cells without liquid junction at five values of the total ionic strength, namely 0.1, 0.5, 1.0, 2.0, and 3.0 mol-kg−1 (m), and at nine temperatures from 5 to 45°C. The ionic strength fraction (γB) of LiCl in the mixtures was varied from 0 to 0.9. The values of log γA were found to vary linearly with the molality of salt, in accordance with the ‘Harned rule,’ indicating that the properties of these mixtures are determined primarily by binary ionic interactions of the type H-Li and that ternary interactions are not significant even at I=3m. The results also support the suggestion of Robinson that the interaction parameter θH,Li is insensitive to temperature changes when I is less than 2m.