Redox Potential

Definition - What does Redox Potential mean?

Redox potential is defined as the specific indicator of the extent to which the oxidizing as well as reducing powers of a substance which has both reducing and oxidizing ingredients, have achieved equilibrium.

Redox potential is used as:

  • An indicator of electrochemical reactivity of substances in environmental conditions
  • For predicting corrosion protection of various substances and systems

Redox is a shortened form of the term oxidation-reduction.

Corrosionpedia explains Redox Potential

Redox potential of a system can be considered as a measure of the intensity of its oxidizing or reducing power, depending on the electrochemical balance.

Oxidation potential measures the power of a substance or system to add oxygen or to remove hydrogen as well as to lose electrons. Reduction potential indicates the power to add hydrogen, lose oxygen or attract electrons.

As the redox potential increases in value and turns positive, its ability to oxidize is enhanced. When it decreases in value and turns negative, its reducing ability is quantitatively enhanced. It has some resemblance to pH value of a liquid.

Any redox reaction can be analyzed as two half-reactions: one half in which a material constituent is oxidized and the other half in which process, another constituent, is reduced.

For the half-reaction such as reduction, the driving power is the negative redox potential. For oxidation, the driving power is the positive redox potential.

As corrosion involves both oxidation as well as reduction, redox potential becomes an indicator of the possibility of electrochemical activity likely to lead to corrosion or resistance to corrosion.

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