A method for the estimation of standard chemical potential differences (Ap") of single ions for the transfer from one solvent to another, derived previously, is applied to the transfer of ions from water to ethanol and ethanol-water mixtures.A similar method is used to estimate the standard partial molar enthalpy of transfer, AH' of single ions, and from these data values for the standard partial entropy of transfer, ASo are obtained.The difference between the standard real potentials of the chloride ion in ethanol and in water has been determined by Case and Parsons. From these data, the corresponding value of Ap' and the surface potential of water, the surface potential of ethanol is determined.