Thermodynamically superfluous reactions

Additional disproportionation and cross-redox reactions associated with the redox system described in Fig. Il.l.ld (Eqs. II.l.l and II.1.2) are difficult to monitor directly by cyclic voltammetry but still may have subtle effects on cyclic voltammetric data. These so-called thermodynamically superfluous reactions [15] can be derived from the voltammetric data because the equilibrium constant data can be calculated from the formal potentials and protonation equilibrium constants. For the resolution of this type of complex reaction scheme, data obtained over a wide range of conditions and at different concentrations are required. 

The proposed approach leads directly to practical results such as the prediction—based upon the chemical potential—of whether or not a reaction runs spontaneously. Moreover, the chemical potential is key in dealing with physicochemical problems. Based upon this central concept, it is possible to explore many other fields. The dependence of the chemical potential upon temperature, pressure, and concentration is the gateway to the deduction of the mass action law, the calculation of equilibrium constants, solubilities, and many other data, the construction of phase diagrams, and so on. It is simple to expand the concept to colligative phenomena, diffusion processes, surface effects, electrochemical processes, etc. Furthermore, the same tools allow us to solve problems even at the atomic and molecular level, which are usually treated by quantum statistical methods. This approach allows us to eliminate many thermodynamic quantities that are traditionally used such as enthalpy H, Gibbs energy G, activity a, etc. The usage of these quantities is not excluded but superfluous in most cases. An optimized calculus results in short calculations, which are intuitively predictable and can be easily verified. 

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