Emf measurements of the cells of the type Pt; H2 (g, 1 atm)/HCl (m) in 5 wt-% 1-butanol, AgCl/Ag at five different temperatures ranging from 5-45°C were used to derive (i) the standard potentials of the silver/silver-chloride electrode, (ii) the mean activity coefficients of HCl, (iii) the primary and secondary medium effects, (iv) the relative partial molal enthalpy, and (v) the thermodynamic constants for the process of transfer of HCl from water to 5 wt-% 1-butanol-water. The thermodynamic functions were calculated from the EN° values and their temperature coefficients for 5 wt-% 1-butanol. The standard emf varied with temperature (t, °C) according to the equation Em° = 0·2029 - 7·135 × 10-4(t - 25) - 15·21 × 10-7(t - 25)2. The molality of the acid ranged from 0·005 to 0·09 mol/kg. The results are discussed in terms of the acid-base properties and the structure of the solvent.
ASJC Scopus subject areas
- Chemical Engineering(all)