Study on tran sport behaviour of Bi(N0 3 )3 in water + DMF/DMSO

Bismuth nitrate is subjected to electrical conductivity studies in water + DMF and water + DMSO at four different temperatures. Limiting molar conductance of Bi(NO 3 ) 3 has been determined at all compositions of DMF and DMSO with water and at different temperatures. Limiting conductance is found to be less in water + DMF mixture than in water + DMSO mixture. Large value of limiting conductance is interpreted due to the release of proton from the co-solvent on account of the action of Lewis acid (Bi 3 + ) on DMF or DMSO in the presence of water. Dissociation and association constants have been calculated. Exothermic nature of the system is supported by the values of thermodynamics of association as well as solvation. Preferential solvation of the cation by the non-aqueous solvent has been observed. Solvation number of the species has been calculated and found to be fractional indicating the formation of solvent separated ion-pair in the system under existing conditions.