Ion-solvation behaviour of Nicotinium dichromate in water-N,N-dimethyl formamide mixtures at 293K

摘要

Molar conductivities of dilute solutions of Nicotinium dichromate, (c 0.0021 eq·dm−3) weremeasured in binary aqueous mixtures containing up to 100 % cosolvent (N, N- dimethylformamide) at 293 K ± 0.1. Data were treated by the Shedlovsky equation, and its parameters,the limiting equivalent conductivity, Λ0, and the association constants, KA, were evaluated.Variations in Walden products and KA were interpreted in terms of ionic properties as well assolvent structure and dielectric constant. The distances of closest approach which weredetermined were compared with those found using the Kraus-Bray equation. The effective ionicradii (ri) of Nicotinium dichromate have been determined from Lio values using Gill’smodification of the Stokes law. The influence of the mixed solvent composition on the solvation ofions has been discussed with the help of ‘R’-factor. Thermodynamic parameters are evaluatedand reported. The results of the study have been interpreted in terms of ion-solvent interactionsand solvent properties.