Some studies of the conductivities of electrolytes in mixed solvents.

The factors which are likely to contribute to discrepancies between theory and experiment for the behaviour of an electrolyte in a solvent are discussed. The more important of these factors are likely to be the non-continuous nature of the solvent and the interaction between the ions and the solvent molecules. The conductivity of silver nitrate in a variety of organic solvents end binary solvent mixtures is measured and values Lambda[o] and K determined. In pure acetone, silver nitrate behaves as an extremely weak electrolyte and. strong acid-base forces are suggested as an explanation of this feet. In acetone solutions containing up to 50% w/w of water and also containing small additions of some pyridine-type bases and other organic compounds, anomalous behaviour is reported. Preferential solvation is considered to be partly responsible for the differences found between the conductivity of the electrolyte in these mixed solvents end that in pure acetone. Both pure benzonitrile and benzonitrile-ethenol solutions were used as solvents and the results are compared with those obtained for the same electrolyte in other solvents end binary solvent mixtures having the seme bulk dielectric constant. The results are explained in terms of specific ion-solvent interaction. The conductivity of silver nitrate was further determined in pure ethylene glycol and in binary mixtures containing water over the complete solvent composition range and in ethylene glycol containing small additions of pyridine and quinoline. The results in pure ethylene glycol are found to be consistent with those in other hydroxylic solvents and the bulk dielectric constant would appear to control the association-dissocietion processfor silver nitrate in this class of solvent. No simple relationship holds, however, for the binary mixtures and preferential solvation is considered to be responsible for these differences