Behaviour of silver-silver oxalate and mercury-mercurous oxalate electrodes in formamide at different temperatures

Abstract

The e.m.f. values of the cells: Pt, H₂|H₂C₂O₄(m)|Ag₂C₂O₄-Ag (A) Pt, H₂|H₂C₂O₄(m)|HgC₂O₄-Hg (B) Hg-Hg₂C₂O₄|H₂C₂O₄(m)|Ag₂C₂O₄-Ag (C) have been measured in formamide at nine temperatures ranging from 5 to 45°C. Values of the standard potentials (E°_m) of silver-silver oxalate and mercury-mercurous oxalate electrodes and values of the e.m.f. of cell (C) can be expressed as equations obtained by using the least squares method: (A) E°_m = 0.44642-1.042x10^-3(t-25)+4.150x10^-6(t-25)² (B) E°_m = 0.39438-1.040x10^-3(t-25)+4.500x10^-7(t-25)² (C) E°_celt = 0.05255-9.750x10^-5(t-25)+8.750x10^-7(t-25)² The standard thermodynamic quantities ΔG°, ΔH° and ΔS^o associated with the corresponding cell reaction have been evaluated for different temperatures.