What is electrode potential?

Electrode potential, also known as redox potential or electrode voltage, is a measure of the tendency of a chemical species to gain or lose electrons when it is involved in a redox (reduction-oxidation) reaction. In simpler terms, it represents the ability of a substance to be oxidized or reduced at an electrode.

The electrode potential is typically measured in volts (V) and is defined with respect to a reference electrode. The standard hydrogen electrode (SHE) is often used as the reference standard for assigning electrode potentials. The electrode potential of the standard hydrogen electrode under standard conditions is defined as zero volts.

There are two types of electrode potentials:

1. Standard Electrode Potential (E°): This is the electrode potential measured under standard conditions, which include a concentration of 1 M for all ions involved in the half-reaction and a pressure of 1 atm for gases. Standard electrode potentials are tabulated and used as a reference for comparing the tendencies of different substances to undergo oxidation or reduction.
2. Electrode Potential Under Non-Standard Conditions (E): This is the electrode potential measured under actual experimental conditions, which may deviate from the standard conditions. The Nernst equation is commonly used to calculate the electrode potential under non-standard conditions:

Electrode potential is a key concept in electrochemistry and is used to predict the direction of redox reactions, as substances with higher standard electrode potentials tend to be reduced, while those with lower standard electrode potentials tend to be oxidized.