Standard potentials of the barium amalgam electrode and thermodynamic functions for dilute barium amalgams and for aqueous barium chloride

The standard potentials of the barium amalgam electrode have been determined over the temperature range 283.15 to 343.15 K from e.m.f. measurements of the cell: Pt|xBa+(1-x)Hg|BaCl2(aq,x)Agcl|AgPt. The results can be reproduced accurately by the equation: E°/V = -1.160117-2.765854×10-3( T K)+3.025048×10-6( T K)2. The standard thermodynamic functions at 298.15 K for the barium amalgam and for the barium amalgamation reaction have also been obtained. In addition, the activity coefficients of aqueous BaCl2 have been determined at molalities up to 0·3 mol kg-1 over the temperature range 283.15 to 343.15 K. The logarithm of the rational activity coefficient of barium in dilute amalgams is a linear function of the mole fraction of barium: log10fBa = QxBa, where Q is temperature-dependent and can be represented by the equation: Q=767.43-4.1793( T K)+0.0060068( T K)2. © 1976.