Thermodynamics of a silver, silver azide electrode in water and water + dioxan at different temperatures

Abstract

The e.m.f. of the cell Ag, AgCl(s)| NaCl(m)⋮ NaN₃(m)| AgN₃(s), Ag in water and water +10, +20, +30 and +40 mass % dioxan has been measured at 5 °C intervals from 5 to 45 °C. The values of the standard potentials of the silver, silver azide electrode have been determined in water and the mixtures at these temperatures. The change in standard thermodynamic quantities (ΔG^⊖, ΔH^⊖ and ΔS^⊖) for the electrode reaction have been evaluated. The thermodynamic parameters for the transfer of HN₃ from water to the mixtures have also been evaluated. The results are discussed in terms of the preferential solvation of ions.