The application of DPASV to the determination of the low temperature solubility of lead sulphate in sulphuric acid solutions

Measurements of the solubility of lead sulphate in 35% by weight sulphuric acid, pure water, and at two intermediate acid concentrations have been made over the temperature range 25 °C to −50 °C using differential pulse anodic stripping voltammetry.Values of the standard enthalpy of solution, derived from the data and from that of other workers, have been found to be higher than those obtained from emf measurements. The extent of lead sulphate ion pairing is analyzed at 25 °C and discussed. The slowness of equilibration of acid solutions supersaturated with lead sulphate was judged of importance in deciding the relevance of the use of thermodynamically calculated lead ion concentrations with respect to lead acid battery mechanisms.

Solvation Enthalpies of Some Alkali Metal and Tetraalkylammonium Salts in Dioxane-Water Mixtures

Enthalpies of solution of LiCl, NaCl, (CH3) 4NBr, (C2H5)4 NBr, (C3H7)4 NBr, and (C4H9)4 NBr in dioxane-water mixtures varying in composition from 20 to 64.5% dioxane have been determined. Values of standard enthalpy of solution, ΔHs0, were obtained using the extended Debye–Hückel equation.Using these ΔHs0 and the lattice energies (U) of these salts, solvation enthalpies have been evaluated.