Effect of ethanol on the solvation behaviour of BiI3 in acetonitrile, methanol and DMF as a function of temperature

This paper reports the results of the investigations carried out on the effect of added ethanol on the conductance behaviour of bismuth tri-iodide in acetonitrile, methanol and dimethylformamide at 288, 298, 308 and 318 K. From the experimental molar conductance value, the limiting molar conductance was determined for all the cases using the Shedlovsky model of conductivity. The limiting molar conductance was found to decrease continuously with the increase in the amount of ethanol either to CH3CN, CH3OH or DMF. In pure solvents, conductance varied in the order of CH3CN>CH3OH>DMF>C2H5OH. Association constant was determined in the three solvent systems. Results predicted the endothermic behaviour of the process in most of the cases. Energy of activation of the conducting rate process and thermodynamic parameters of association were calculated and reported. Walden product and corrected Stokes molecular radius were also computed. The solvation number of the species was calculated in the case of pure solvents and the value indicated the existence of solvent shared or separated ion pair in the system.