The polarographic behaviour of 2-iodonaphthalene has been studied in aqueous mixtures of ethanol, dioxane and acetone containing 1 M lithium chloride. The diffusion current constant is practically unaltered with the solvent concentration. Employing the diffusion coefficients determined by the diaphragm cell method in the Ilkovic Equation the number of electrons involved in the reduction process has been calculated as two. The limitations in employing the diffusion coefficients obtained by equivalent conductivity and viscosity methods for arriving at the reduction mechanism have been pointed out.
The half-wave potential shifts to more negative values with an increase in the concentration of the organic solvent. The values of E3/2-E1/2 have been found to be of the order of 0·1 V. indicating the irreversibility of the electrode process.