Standard Potentials of the Silver-Silver Iodide Electrode in Diethylene Glycol-Water Mixtures at Different Temperatures and the Related Thermodynamic Quantities

Standard electrode potentials of the silver-silver Iodide electrode were determined at four temperatures In the temperature range 5-35 °C in 20, 40, 60, and 80 wt % diethylene glycol-water mixtures by emf measurements on the cells Pt, H2(g, 1 atm)|HBO2(m1),NaBO2(m2),KBr(m3)[dlethylene glycol (x)-water (y)]|AgBr-Ag and Pt, H2(g, 1 atm)|HBO2(m1),NaBO2(m2),KI(m3)[diethylene glycol (x)-water (y)]|AgI-Ag. The standard molal potential, sE°m,In the various solvent mixtures is expressed as a function of temperature. The various thermodynamic parameters for the transfer of HI from water to these media at 25 °C are reported and the variation of these parameters with solvent composition Is discussed both in terms of the basicity of the solvent mixtures and also In terms of their structural effects on the transfer process. The standard molal free energies of transfer of the H+ and the hallde ions are also evaluated at 25 °C on the basis of the Feakins extrapolation method In these mixtures. © 1979, American Chemical Society. All rights reserved.