POLAROGRAPHIC BEHAVIOR OF THE VIOLOGEN INDICATORS

Abstract

The polarographic behavior of 1,1′-dimethyl- and 1,1′-dibenzyl-4,4′-bipyridinium dichloride has been investigated over the pH range of 1 to 13. Reversible reduction waves are obtained for the first single-electron step for both compounds. The second step is electrochemically irreversible but evidence is presented to indicate that the second step is fleetingly reversible at the dropping mercury electrode for methyl viologen but not benzyl viologen. Minor waves due to adsorption of the reduced viologen on the surface of the mercury have been observed.