What role does an oxidising agent play in a chemical reaction?

An oxidising agent is a substance that accepts electrons during a chemical reaction, thereby facilitating the process of oxidation in another substance. When a chemical reaction occurs, the oxidising agent undergoes a reduction process, meaning it gains electrons and, as a result, decreases in oxidation state.

This role is vital in redox (reduction-oxidation) reactions, which involve the transfer of electrons between species. For example, in a reaction where a metal is oxidised, the oxidising agent is the one that gains the electrons that the metal loses, causing the metal to oxidise and the oxidising agent to be reduced.

This concept fundamentally contrasts with the roles of other types of agents in reactions. A substance that donates electrons is known as a reducing agent and increases the oxidation state of itself while reducing another. Furthermore, the oxidising agent does not inherently increase pH, nor does it remain unchanged in terms of its oxidation state during the reaction since it is affected by the transfer of electrons.