No abstract

Electromotive force measurements of cells of the type Pt, H2 (g, 1 atm)/HCI (m) diethylene glycol(x)-water(y)/ AgCI-Ag were carried out at five temperatures in the temperature range 5-45°C in 20, 40, 60, and 80 wt % diethylene glycol-water mixtures to evaluate the standard potentials of the Ag-AgCI electrode in the above mixtures, the primary medium effects, the mean molal activity coefficients in the concentration range 0.01-0.1 mol Kg'1, and the various thermodynamic quantities for the transfer of HCI from water to these media. The standard molal potential, sEm°, in all the solvent mixtures was expressed as a function of temperature. The significance of the various thermodynamic quantities associated with the transfer process is discussed both in relation to the acid-base nature of the solvent mixtures and also the structural effects of these solvent mixtures on the transfer process. The standard molar Gibbs free energy of transfer, AG¡(CI°, was a linear function of log 4>w ( , = volume fraction of water) in the various mixtures and from the slope, n; i.e., the number of water molecules coordinated to HCI evaluated was 2.0.

No abstract

For AlSO+4 and GaSO+4 the thermodynamics and kinetics of the reaction outer‐sphere complex → inner‐sphere complex have been investigated with the pressure‐jump relaxation technique. From measurements between 10 and 40 °C the rates and energies of activation have been obtained. The equilibrium constants were estimated from the amplitudes of the relaxation effects.

The selective solvation of Ag(I) bromate and iodate was studied in dimethyl sulfoxide–water mixtures at 30 °C by solubility and EMF measurements. The solubility of silver bromate decreases down to XDmso=0.2 and thereafter increases with addition of dimethyl sulfoxide, the solubility of silver iodate continuously decreasing under the same conditions. The transfer free energy of silver cation decreases while that of halate ions increases with the addition of dimethyl sulfoxide. The solvent transport number, Δ, passes through a maximum around XDmso=0.5 in both cases. These results were interpreted in terms of a heteroselective solvation of both the salts, the silver ion being preferentially solvated by dimethyl sulfoxide and the halate ions selectively hydrated by water in the mixtures.