24.2.6—From E

A species on the left of a reduction half-equation is an oxidising agent because it accepts electrons. More positive E° means a stronger tendency to be reduced and therefore a stronger oxidising agent.

The reduced form is the corresponding reducing agent; a more negative E° for its reduction half-equation generally indicates a stronger reducing form. Compare like half-equations and conditions.

Cl₂/Cl⁻ has a more positive E° than I₂/I⁻, so chlorine is the stronger oxidising agent and iodide is the stronger reducing agent.

Do not rank the products of a half-equation as oxidising agents; identify which side gains electrons.