Standard potentials of aqueous solutions

Readers are referred to the article Potentiometry [P 2 115] in the treatise Analysis and Characterization, and to the article Electrochemistry [D 990] in the treatise Electrical Engineering.

The electrochemical standard (equilibrium) potential is a thermodynamic quantity. As such, it is predictive, i.e. useful in many applications.

The value of this quantity is expressed in relation to a reference system. In theory, it should only depend on the electrochemical couple under consideration and the medium (solvent) in which it is placed.

Water is the most widely used solvent. Aqueous solutions are therefore of obvious interest, which is why the tables presented in this article concern only this type of solution, as defined by the IUPAC (International Union of Pure and Applied Chemistry) .

To make the most of the table of standard potentials, a few preliminary points may be useful. These concern, on the one hand, the notion of electrochemical equilibrium and, on the other, the conditions necessary for the disequilibrium of an electrochemical system, followed by the practical consequences.