The principle of Electrical conductivity is used in the study of ion-solvation of Citric acid in water, water+CH3CN and water+DMSO mixtures (v/v) in the temperature range 283-313K. The conductance data were analyzed by Kraus-Bray and Shedlovsky conductivity models. Limiting molar conductance (λm 0), dissociation constant (KC) and association constant (Ka) were evaluated for all the solvent compositions. The λm 0 values decreases with the addition of cosolvent CH3CN or DMSO, due to increased solvent-solvent interaction and decrease in dielectric constant. The λm 0 of water+DMSO mixture is smaller than that in water+CH3CN mixture. The KC values increases with increase in temperature in all the compositions of solvent mixtures. Energy of activation of the rate process and related thermodynamic parameters has been computed. Using viscosity of solvent/solvent mixture, Walden product and corrected Stoke’s radius (ri) have also been computed. To identify the formation of ion-pairs and ion-triplets, a plot was drawn on the basis of Fuoss equilibrium equation, the slopes of the plot were found to be around -0.5, indicating the presence of ion-pairs or ion-triplets. These computed values have been used to discuss qualitatively the nature of ion-solvent interaction of Citric acid with water, water+CH3CN and water + DMSO mixture.
