Redox reactions in aqueous solution

Although In(I) can be obtained in low concentration by oxidation of an In anode in dilute HCIO4, the solution 

The potential diagram for indium in acidic solution (pH = 0) is given below with standard redox potentials given in V  

The most rigorous method is to determine AG°(298K) for each step, and then to calculate for the In /ln couple. However, it is not necessary to evaluate AG° for each step instead leave values of AG° in terms of the Faraday constant (see worked example 8.7). 

Reduction of In to In is a 3-electron process, and is found fi om the corresponding value of AG°  

Construct Frost-Ebsworth diagrams for Ga, In and T1 at pH = 0. Use the diagrams to comment on (a) the relative abilities of Ga , In and tF to act as oxidizing agents under these conditions, and (b) the relative stabilities of the -fl oxidation state of each element. 

The standard reduction potentials for the M /M couples (Table 13.1) show that Al (aq) is much less readily reduced in aqueous solution than are the later ions. This can be attributed, in part, to the more negative Gibbs energy of hydration of the smaller Al ion. However, an important contributing factor (scheme 13.71) in differentiating between the values of for the Al /Al and Ga /Ga couples is the significant increase in the sum of the first three ionization energies (Table 13.1). 

Although In(I) can be obtained in low concentration by oxidation of an In anode in dilute HCIO4, the solution rapidly evolves H2 and forms In(III). A value of —0.44 V has been measured for the In +/In+ couple (equation 13.72). 

The standard reduction potentials for the M /M couples (Table 12.1) show that Al (aq) is much less readily reduced 

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Figure 10-3 juxtaposes the Fermi levels of the following redox reactions in aqueous solutions and the quasi-Fermi levels of interfacial electrons and holes in an n-type semiconductor electrode erhjo/Hj) of the hydrogen redox reaction F(0a/H20) of the oxj en redox reaction ersc) of the n- q)e semiconductor and... 

Quinones are among the best-behaved organic compounds to undergo redox reactions in aqueous solutions. There are a reasonably large number of synthetic and natural products containing the quinone moiety, and many are excellent candidates for selective determination by LCEC. Unfortunately, some of the most important of these compounds are extremely hydrophobic due to the presence of long hydrocarbon side chains, and are therefore quite difficult to study by reversed-phase LC. 

Savinov E. N., Photocatalysis of redox reactions in aqueous solutions with dispersed metals and semiconductors, D.Sc. Thesis, Novosibirsk (1993) (in Russian). 

Balance equations for redox reactions in aqueous solution, using the halfreaction method, and calculate the concentrations of substances during redox titrations (Section 11.4, Problems 27-40). 

Table 3.6. Some Second-Order Rate Constants for Inner-Sphere and Outer-Sphere Redox Reactions In Aqueous Solution...

Chapter 10 Reattions in Aqueous Solutions I Acids, Bases, and Salts) and Chapter 11 (Reactions in Aqueous Solutions II Calculations) include comprehensive discussions of acid-base and redox reactions in aqueous solutions and solution stoichiometry calculations for acid-base and redox reactions. 

With Equation 5.24, we can calculate a useful approximation of the reversible potential on a specific catalyst surface using the adsorption energies of each species involved in the reaction, if we know the reversible potential of a redox reaction in aqueous solution, or we can calculate the shift of the onset reversible potential between two unlike catalyst surface compositions if the absolute reversible potential in aqueous phase for a specific redox reaction is not known. For example, the change in onset reversible potential due to a Pt surface and an alloy will be... 

BUal B. A. and Muller E. (1992), Thermodynamic study of cerium(4+)/cerium(3+) redox reaction in aqueous solutions at elevated temperatures 1. Reduction potential and hydrolysis equihbria of cerium(4+) in perchloric acid solutions , Z. Naturforsch., A Phys. Set, 47, 974-84. 

Mehrotra RN (1981) Kinetics and mechanisms of redox reactions in aqueous solution. Part 7. Decarboxylation of aliphatic acids by aquasilver(II) ions. J Chem Soc Dalton Trans 897-901... 

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