Synthesis of the Overall Kinetics

It is easy to derive the expression for the overall net rate i from the component rates of the two steps. From Eqs. (53), (54), (60), and 

It is seen that the rate-controlling nature of the two steps basically depends on relative magnitudes of the two terms in the denominator of this equation, particularly on the ratio of iov to /ot, and further depends on the magnitude of the overpotential included in the second term. This is particularly so as ya increases with the negative increase of 17. Thus, the ratio of the two terms, r, viz.. 

This route can be analyzed similarly major results are  

However, one finds a significant difference in the meaning of the break from that currently understood. As already mentioned in the footnote to Eq. (47), it is not generally true that such a break is caused by saturation with H(a) of the electrode surface. Suppose that do is sufficiently small that Z and O can both be approximated to unity [cf. Eq. (52)]. If mao 1, then for large cathodic overpotentials, Eq. (80) yields 

Suppose now that 0 is close to unity. With 0 = 1, Eq. (81) reduces to 

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