Editing Electrode potential (section)

==Sign conventions==
Historically, two conventions for sign for the electrode potential have formed:<ref name="ham">C.A. Hamel, "The Encyclopedia of Electrochemistry", Reinhold Publishing Corporation, New York-Chapman & Hall Ltd., London, 1964, p. 429–431.</ref>
# convention "[[Walther Nernst|Nernst]]–[[Gilbert Newton Lewis|Lewis]]–[[Wendell Mitchell Latimer|Latimer]]" (sometimes referred to as "American"),
# convention "[[Josiah Willard Gibbs|Gibbs]]–[[Wilhelm Ostwald|Ostwald]]–[[Stockholm]]" (sometimes referred to as "European").

In 1953 in Stockholm<ref>P. van Rysselberghe, "Bericht der Kommission für electrochemische Nomenklatur und Definitionen", Z. Electrochem., 58 (1954), 530–535.</ref> IUPAC recognized that either of the conventions is permissible; however, it unanimously recommended that only the magnitude expressed according to the convention (2) be called "the electrode potential".  To avoid possible ambiguities, the electrode potential thus defined can also be referred to as ''Gibbs–Stockholm electrode potential''. In both conventions, the standard hydrogen electrode is defined to have a potential of 0 V. Both conventions also agree on the sign of {{mvar|E}} for a half-cell reaction when it is written as a reduction.

The main difference between the two conventions<ref>Anson, Fred C. "Common sources of confusion; Electrode Sign Conventions," J. Chem. Educ., 1959, 36, p. 394.</ref> is that upon reversing the direction of a half-cell reaction ''as written'', according to the convention (1) the sign of {{mvar|E}} also switches, whereas in the convention (2) it does not. The logic behind switching the sign of {{mvar|E}} is to maintain the correct sign relationship with the [[Gibbs free energy]] change, given by {{math|1=Δ''G'' = −''nFE''}} where {{mvar|n}} is the number of electrons involved and {{mvar|F}} is the [[Faraday constant]]. It is assumed that the half-reaction is balanced by the appropriate SHE half-reaction. Since {{math|Δ''G''}} switches sign when a reaction is written in reverse, so too, proponents of the convention (1) argue, should the sign of {{mvar|E}}. Proponents of the convention (2) argue that all reported electrode potentials should be consistent with the electrostatic sign of the relative potential difference.