Distinction between Intermediates Produced in Main and Side Electrodic Reactions

A diagnostic criterion was developed to distinguish between an intermediate formed in an over-all reaction path and a product in a parallel electrochemical reaction. It utilizes the method of the rotating-disk electrode with a concentric ring, first proposed by Frumkin and Nekrassov. From the dependence of currents at the disk and at the ring electrode on the rate of disk rotation, individual rates of parallel reactions can be obtained.