The thermodynamic study of the system LiCl–KCl–H2O at the temperature 298.15 K

The mixture electrolyte {yLiCl+(1−y)KCl}(aq) has been studied by the hygrometric method at 298.15 K. The water activities are measured at total molalities from 0.3 mol kg−1 to about saturation for different ionic-strength fractions y of LiCl with y=0.33, 0.50, and 0.67. The results allow the deduction of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson, Kusik and Meissner, Robinson and Stokes, Lietzke and Stoughton, Reilly–Wood and Robinson, and Pitzer models. From these measurements, the new Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture. The excess Gibbs energy is also determined.