What occurs during step 2 of the cyclic voltammetry process?

In cyclic voltammetry, step 2 typically involves the reduction of a species that has been oxidized in the prior step. During this phase, as the potential is scanned back in the opposite direction, the current initially rises to a peak due to the rapid reduction of the species that is still present in solution. This increase in current corresponds to the concentration of the electroactive species being transformed from its oxidized form back to its reduced form.

As the reduction proceeds and the concentration of the species decreases, the current starts to decline, reflecting the depletion of the reduced species in that specific area of the electrode surface. The peak current occurs because there is an optimal concentration gradient that drives charge transfer, but as the reactant is consumed, that gradient diminishes, leading to a decrease in current.

Thus, the process is characterized by the initial peak in current followed by a decline which is a hallmark of controlled cyclic voltammetry, making the first choice the correct and most representative description of step 2.