electrode potential

Electrode potential, <i>E</i>, in chemistry or <a href="https://en.wikipedia.org/wiki/Electrochemistry" title="Electrochemistry">electrochemistry</a>, according to a <a href="https://en.wikipedia.org/wiki/IUPAC" title="IUPAC">IUPAC</a> definition,^{<a href="https://en.wikipedia.org/wiki/Electrode_potential#cite_note-1">[1]</a>} is the <a href="https://en.wikipedia.org/wiki/Electromotive_force" title="Electromotive force">electromotive force</a> of a<a href="https://en.wikipedia.org/wiki/Galvanic_cell" title="Galvanic cell">cell</a> built of two <a href="https://en.wikipedia.org/wiki/Electrode" title="Electrode">electrodes</a>:

• on the left-hand side is the <a href="https://en.wikipedia.org/wiki/Standard_hydrogen_electrode" title="Standard hydrogen electrode">standard hydrogen electrode</a>, and
• on the right-hand side is the electrode the potential of which is being defined.

By <a href="https://en.wikipedia.org/wiki/Convention_(norm)" title="Convention (norm)">convention</a>:

From the above, for the cell with the <a href="https://en.wikipedia.org/wiki/Standard_hydrogen_electrode" title="Standard hydrogen electrode">standard hydrogen electrode</a> (potential of 0 by convention), one obtains:

The left-right convention is consistent with the international agreement that redox potentials be given for reactions written in the form of reduction half-reactions.

Electrode potential is measured in <a href="https://en.wikipedia.org/wiki/Volt" title="Volt">volts</a> (V).

Electrode potential is defined as the potential of a cell consisting of the electrode in question acting as a cathode and the standard hydrogen electrode acting as an anode. Reduction always takes place at the cathode, and oxidation at the anode.