Faradaic rectification parameters

The present chapter will cover detailed studies of kinetic parameters of several reversible, quasi-reversible, and irreversible reactions accompanied by either single-electron charge transfer or multiple-electrons charge transfer. To evaluate the kinetic parameters for each step of electron charge transfer in any multistep reaction, the suitably developed and modified theory of faradaic rectification will be discussed. The results reported relate to the reactions at redox couple/metal, metal ion/metal, and metal ion/mercury interfaces in the audio and higher frequency ranges. The zero-point method has also been applied to some multiple-electron charge transfer reactions and, wheresoever possible, these results have been incorporated. Other related methods and applications will also be treated. 

From the derivations in Appendix B, it is evident that the present faradaic rectification formulations for multiple-electron charge transfer not only enable the determination of kinetic parameters for each step of three-electron charge transfer processes but may also be extended to charge transfer processes involving a higher number of electrons. However, the calculations become highly involved and complicated. 

Recently, the kinetic parameters for each step of this reaction in different supporting electrolytes have been obtained39,42 by applying the faradaic rectification theory as extended to multiple-electron charge transfer reactions. The kinetic parameters are listed in Table 1. 

By applying the recently developed theory of faradaic rectification as applied to multiple-electron charge transfer reactions under the condition that k° and C°R = 1. Kinetic parameters are obtained for each step of the electron charge transfer. The value of /c° reported is of the order of 10 6 to 10-9 cm/s whereas that of fc is of the order of 10 3 cm/s in different supporting electrolytes.51... 

Faradaic rectification polarographic studies have been carried out for a mixture containing several metal ions together and also for individual inorganic depolarizers so as to explore the applicability and limitations of the method and to determine kinetic parameters for some of them. For comparison, some of the dc and ac polarograms have also been recorded simultaneously. In the following, the details of the experimental technique used will be described and the potentiality of the technique in qualitative and quantitative analysis will be examined. The applicability of the method in the... 

The reduction of zinc ions at d.m.e. has widely been studied and the reaction has been reported to be quasi-reversible.94 Van Der Pol and co-workers54 studied this reaction by the faradaic rectification polarographic technique using high-frequency modulated signals. The kinetic parameters have been evaluated by the... 

Earlier studies generally involved the evaluation of kinetic parameters of reactions which are accompanied by single-electron charge transfer.116 Some reactions involving two-electron charge transfer were also studied, assuming either that both electrons are transferred in a single step or that the slower step in the two-step reaction is in overall control of the rate process. As described in this chapter for the first time, the faradaic rectification theory for... 

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