Driving Force of a Redox Couple (Potential Difference)

Quantifies the driving force of electron flow. Electrons move from the lower effective reduction potential (anode) to the higher one (cathode); a larger difference means a stronger driving force and a more aggressive oxidizer.

$$\Delta E=E_{\text{cathode}}-E_{\text{anode}}$$

Variables

Symbol	Meaning	Unit
$\Delta E$	potential difference (driving force) between the two materials or species	V
$E_{\text{cathode}}$	effective reduction potential of the electron acceptor (cathode)	V
$E_{\text{anode}}$	effective reduction potential of the electron donor (anode)	V

Worked example

Ozone at about 2.07 V acting on iron creates a far larger driving force than dissolved oxygen at about 1.23 V, so ozone is the more aggressive oxidizer.

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Part of The Blueprint of Water