The standard potentials (E") of the silver/silver-iodide electrode in aqueous mixtures of ethylene glycol (containing 10,30,50,70 and 90 wt-o/o glycol) have been determined from emf measurements of the cell Pt, Hl(g, 1 atm)/HOAc(ml), NaOAc(m*), KI(m,), solvent/AgI/Ag at nine temperatures ranging from 5 to 45°C. These E" values have been utilized to compute free energy (AG,"), entropy (AS,") and enthalpy (AH,") changes accompanying the transfer of HI from water to each of the solvents. These values as well as those for HCl and HBr obtained earlier have also been utilized to evaluate A&O(i) for individual ions by a method of 'simultaneous extrapolation,' which in turn furnished the values of AHto for these ions. These quantities and also the 'chemical' contributions for the halide ions as obtained by subtracting the 'electrostatic' contribution computed with the Born equation, have been examined in the light of ion-solvent interactions as well as the structural changes of the solvents. The observed results conform with what is expected from the competitive effects of the preferential solvating capacities of water towards halide ions and that of other solvents towards hydrogen ions, and also of the effects arising from the structural changes of the solvents that are likely to occur in the over-all transfer process.