Re-determination of the standard electrode potential of zinc and mean molal activity coefficients for aqueous zinc chloride at 298.15 K

Abstract

The e.m.f. of the cell Zn–Hg(2-phase)|ZnCl₂(aq.)Agcl, Ag has been measured using zinc chloride solutions in the concentration range 1.0 × 10^–4–1.0 mol kg^–1 at 298.15 K. Stable potentials in very dilute solutions have been obtained by use of amalgamated zinc rod (in place of liquid amalgam). The standard potential of the cell, E°, is 984.28, σ= 0.15 mV, from which E^°_Zn=–761.94, σ= 0.15 mV, and was obtained by two independent methods. The solutions show significant complex formation at concentrations above 0.01 mol kg^–1. Mean molal activity coefficients have been calculated at concentrations up to 1.0 mol kg^–1.