Studies of electrical moment and thermodynamic properties of water in organic solvents at 298.15Â K

We report in this paper on measurements of static dielectric constant (ε) at 1 kHz for solutions of water dissolved in organic solvents (benzene and 1,4-dioxane) of low dielectric constant at 298.15 K. The solutions having different water activities and hence concentrations were prepared by isopiestic technique. The solubility data indicate validity of Henry's law only near solutions of unit water activity. The variation of ε with concentration of water is subjected to analysis using the Kirkwood-Fröhlich equation. The calculated dipole moment values (μ) for water molecules indicate presence of monomers in 1, 4-dioxane solutions while μ values in case of the H2O-benzene system reveal change of monomer to cyclic-trimer species. Also, an attempt is made to apply McMillan-Meyer theory to the data of the H2O-benzene system. The results of these indicate presence of pair and triplet interactions (osmotic virial coefficients) for water molecules in the condensed phase.