Pitzer and Pitzer–Simonson–Clegg ion-interaction modeling approaches: Ternary HCl+methanol+water electrolyte system

Abstract: Clegg–Pitzer–Brimblecombe ion-interaction semi-empirical approach was rarely exploited for modeling electrolyte, particularly, in mixed solvent systems. Indeed, a review of the literature shows that the use of an exact and complete form of this model (PSC) was only limited to the works of two research groups for the investigation of electrolyte in mixed solvent systems. In this work, we have used both Pitzer and PSC ion-interaction theoretical approaches for modeling the non-ideal behavior of HCl in the ternary HCl+methanol+water electrolyte system. The modeling purposes were achieved based on the experimental determination of the mean molal activity coefficients for HCl in this ternary system by using the potentiometric data of a galvanic cell containing a pH glass membrane and Ag/AgCl electrodes. The measurements were performed over the electrolyte molality ranging from 0.01 up to 5.75mol/kg in mixed methanol (x%)+water (100− x%) solvent, with solvent mass fraction percents: x%=10, 20, 30, 40 and 50%, at 298.15±0.05K. [Copyright &y& Elsevier]