Thermodynamics of Hydrochloric Acid in 8.03, 20.76, 44.04, 70.28, and 87.71 Weight % 2-Propanol-Water Mixtures from E.M.F. Measurements at 0°, 15°, 25°, and 35°C

The electromotive force measurements of the cell, Pt, H₂ (1 atm) | HCI (m), 2 -propanol (X), water (Y) | AgCI, Ag were made for 8.03, 20.76, 44.04, 70.28, and 87.71 weight % 2-propanol at 0°, 15°, 25°, and 35° C. The cell was used to derive the standard e.m.f. of this cell for 2-propanol-water mixtures by using a polynomial curve-fitting technique, the mean activity coefficient of hydrochloric acid, the primary and secondary medium effects, the relative partial molal heat content and heat capacity of HCI, and the means of converting the values obtained from the mixed- solvent systems to those of the standard reference aqueous state. The curve-fitting program permits evaluation of the standard potential in mixed solvents, with elimination of some of the uncertainties encountered in the conventional linear graphical extrapolations where previous knowledge of the dielectric constant of the solvent, density of the mixed-solvent, and the ion-size parameter is required. The molality of HCI ranged from 0.1 to 0.001 mole kg ^-1.