Thermodynamic properties of hydrobromic acid in ethanol + water solvent mixtures from electromotive force measurements at 15–55°C

From the electromotive force measurements of cells of the type: Pt, H₂ (gas, 1 atm); HBr (m), ethanol + water solvent mixtures; AgBr, Ag, at nine different temperatures in the range 15–55°C and in the molality range of HBr from 0.005 to 0.1 mol kg^?1, the standard potentials of silver—silver bromide electrode have been determined in twenty ethanol + water solvent mixtures covering the whole range of solvent composition. The temperature variation of the standard potential was utilized to calculate the standard thermodynamic functions for the cell reaction, the primary medium effects of various solvents upon HBr, and the standard quantities for the transfer of HBr from the standard state in water to the standard states in the respective solvent media. The results have been interpreted in regard to the acid-base properties and structure of the solvents.