Thermodynamics of Cadmium Amalgam Electrode in Aqueous Medium

From e.m.f. measurements of the cell: Pt|CdxHg1-x|CdCl2,aq, m = 0.1 mol kg-|AgCl|Ag|Pt over the temperature range from 288.15 to 308.15 K, the standard potential of the cadmium-amalgam electrode has been determined, which can be reproduced by the equation: E°Cd + Hg V = -0.3736907 - 2.099557 × 10-5( T K)2. The parallel values of the standard potential of the cadmium electrode have also been recalculated from data in the literature and have been found to be representable by E°Cd V = -0.1991361 - 1.29106×-3( T K)+2.099557×10-6( T K)2. From ECd + Hgo and ECdo have been determined the standard thermodynamic functions at 298.15 K for the cadmium amalgamation reaction and for the species: cadmium amalgam, CdCl2(aq) and Cd2+(aq). Dilute cadmium amalgams behave as regular solutions as substantiated by the linear relation between the logarithm of the rational activity coefficient of cadmium in amalgam and the corresponding mole fraction: log10f{hook}Cd = Qx, where in turn the parameter Q is a linear function of temperature: Q = 0.039362+8.3999×10-4( T K).