Studies on the Rising Portion of Reversible Polarographic Waves

Polarographic Reduction of the Phenyl-Substituted Ethenes

“…The ;~ function.--The fl function is defined as the ratio of (i/i)E. For reversible processes involving a soluble reduced product, the expanding spherical electrode theory (12) predicts that fl should be nearly constant and slightly less than 0.857, i.e., 6/7, throughout the whole wave. On the basis of this theory fl can be represented by the equation According to planar electrode theory, fl should be 3/5 at the base of an irreversible wave and 6/7 at the head (13); these predictions agree with those of the spherical electrode theory.…”

“…The ;~ function.--The fl function is defined as the ratio of (i/i)E. For reversible processes involving a soluble reduced product, the expanding spherical electrode theory (12) predicts that fl should be nearly constant and slightly less than 0.857, i.e., 6/7, throughout the whole wave. On the basis of this theory fl can be represented by the equation…”

“…At the head of the wave, the following equation applies (17), 1/knet = 1/(knet)l -~-1/(knet)2 [12] where (knet)l refers to the net rate if only the second reaction were rate-determining and (knet)2 if only the third reaction were. The log plot slope at the head of the wave, obtained by substituting Eq.…”

“…[9] and [11] into Eq. [12] and differentiating the resulting expression, is alnl/O.059. Because of the disagreement noted between the log plot slope predictions of the planar and expanding spherical electrode theories in the case of a very fast, i.e., reversible, electrochemical reaction preceding an irreversible one (16), the conclusions regarding log plot slopes for two consecutive slow electrochemical reactions arrived at by the equivalent reaction pair theory are to be preferred to those deduced from planar electrode theory (18), even though the equivalent reaction pair equations for currents would not be of the correct form according to expanding spherical electrode theory.…”

Polarographic Theory, Instrumentation, and Methodology

“…Studies involving slow solution reactions, slow electrode reactions, or both, have been made by Delahay and his coworkers (15,40,48,51,257), Hush, Oldham, and their associates (61,129,132,211,212), and others (10, 70, 89,126,127,201,221). Most of these papers are mathematical, and for a straightforward and very readable discussion of currents controlled by reaction rates, the reader is referred to the review by' XX'iesner (279), a pioneer in the field, whose early simple theory of kinetic waves has been shown to be essentially correct by Koutecky's more recent rigorous derivations.…”