This book is intended to serve as both a course text at the senior-graduate level and as a reference book for those who wish to evaluate electrochemical methods as research tools. It should find wide use for both purposes. The content is narrower than the title may suggest. It is restricted to those aspects of electrochemistry in which the interplay of current flow and mass transfer at a microelectrode is of central importance.The first four chapters, which provide background for the rest of the text, assume the usual undergraduate physical chemistry background. Following a concise survey of electrode processes, there are brief treatments of the thermodynamics of electrochemical cells, electrode kinetics, mass transfer processes, and the nature and significance of current-potential curves.Chapters 5-12 comprise the heart of this text, and they are concerned mainly with developing in detail the equations that describe mass transport controlled electrode reactions under the conditions of the standard experiments. Both perturbation methods and steady-state methods are treated,

The current-voltage curve for the reduction of Cu(II) in 2M HC1 at the G.C.E. has two distinct peaks in contrast with that for the reduction at the P.G.E. which gives only one discernible peak. Both waves are easily measured and increase in direct ratio to an increase in Cu(II) concentration.Presumably, these peaks represent the reductions

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Flash photolysis of neutral red between pH 1.3 and pH 11 yields the triplet species -'DH;*, 3DH+, and 'D. Both 3DH;2, and 'D exhibit first order decay with rate constants of 1.6 k 0.3 x 104 s-', but 3DH+ decays within the lifetime of the flash. Over the entire pH range, ascorbic acid quenches the triplet, forming the semireduced radicals DH:2, DH; and DH., all of which exhibit second order decay with k = 1.8 k 0.4 x 108 M-' s-', most probably by recombination with semioxidized ascorbic acid. The dependence of the rate of decay of radical neutral red on the identity of reversible reductants supports the back-electron transfer mechanism, as does digital simulation of complex radical disproportionation schemes. In contrast to the efficient reduction of triplet neutral red by ascorbic acid, its reduction by EDTA is quite inefficient.

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Kinetics of Electrooxidation of Chromium in Perchlorate 1213 it is formed by an intramolecular isomerization which does not involve a thermal free radical. In the analogous alkyl chloride system it has been found8 that n-C3H7Cl is isomerized to í-C3H7C1 by radiation in a chain reaction catalyzed by HC1, (/-values in excess of 100 being observed. This chain is eliminated by low concentration of la. The isomerization appears to occur by the sequence Cl + n-C3H7Cl CH3CHCH2C1 + HC1; CHr CHCH2CI ^CH.CHC1CH,; CH3CHC1CH2 + HC1 -í-C,HtC1 + Cl, Cl + n-C3H7Cl CH3-CHCH2CI + HCI, etc. It may be that CH3CH-CH2Br radicals occasionally isomerize and are stabilized by a similar mechanism. Such a possibility is consistent with our data and could account for the effect of added Br2 on (?(i-C3H7Br).

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