Activity Coefficients of HCl + GdCl3 +H2O System from 5 to 55°C. Application of PitzerFormalism

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• 作者：Roy ; Rabindra N. ; Gregory ; Darin R. ; Roy ; Lakhsmi N. ; Pierrot ; Denis ; Millero ; Frank J.
• 关键词：Hydrochloric acid ; gadolinium chloride ; emf ; Harned's rule ; Pitzer equations ; activity coefficients ; mixtures of electrolytes
• 刊名：Journal of Solution Chemistry
• 出版年：2000
• 出版时间：2000
• 年：2000
• 卷：29
• 期：7
• 页码：619-631
• 全文大小：139 KB

文摘

The emf of the cellwithout a liquid junction was used to investigate the HCl + GdCl$\_3$ + H$\_2$O mixedelectrolyte system. The emf of the cell was measured for HCl + GdCl$\_3$ + H$\_2$Osolutions at ionic strengths of 0.025, 0.05, 0.1, 0.5, 1.0, 1.5, and 2.0 mol-kg$^-1$and at eleven temperatures ranging from 5 to 55°C at 5°C intervals. The meanactivity coefficients for HCl in the mixtures were determined using the Nernstequation. About 793 experimental emf data points were treated by the Harnedequations. Results show that hydrochloric acid follows Harned's rule at all ionicstrengths, but the quadratic term is needed for I = 1.5 mol-kg$^-1$. Theion-interaction treatment of Pitzer was used to evaluate the results. The binary andternary mixing parameters at 25°C were found to be ??$\_H,Gd$ = 0.07 ± 0.03 andΨ$\_H,Gd,Cl$ = 0.14 ± 0.03. These values were determined using literature values ofβ$^(0)$, β$^(1)$, and C$^\psi$ for GdCl$\_3$ at 25°C and estimates of the effect of temperaturefrom 5 to 55°C using enthalpy and heat capacity data.