Standard electrode potential

In an electrochemical cell, an electric potential is created between two dissimilar metals. This potential is a measure of the energy per unit charge which is available from the oxidation/reduction reactions to drive the reaction. It is customary to visualize the cell reaction in terms of two half-reactions, an oxidation half-reaction and a reduction half-reaction.

Standard Reduction Potentials

As stated above, the standard reduction potential is the likelihood that a species will be reduced. It is written in the form of a reduction half reaction. An example can be seen below where "A" is a generic element and C is the charge.

Standard Reduction Potential


For example, copper's Standard Reduction Potential of Eo=+0.340V)Eo=+0.340V) is for this reaction


Standard Oxidation Potentials

The standard oxidation potential is much like the standard reduction potential. It is the tendency for a species to be oxidized at standard conditions. It is also written in the form of a half reaction, and an example is shown below.

Standard Oxidation Potential (SOP) under standard conditions:


Copper's Standard Oxidation Potential



The standard oxidation potential and the standard reduction potential are opposite in sign to each other for the same chemical species.

Relation Between Standard Reduction Potential (SRP) and the Standard Oxidation Potential (SOP) Eo0(SRP)=−Eo0(SOP)