Identify oxidation and reduction with their agents: $2\mathrm{Al}+{\mathrm{Fe}}_2{\mathrm{O}}_3$ gives $2\mathrm{Fe}+{\mathrm{Al}}_2{\mathrm{O}}_3$.

Redox Reaction

1. Oxidation is a process that involves the addition of oxygen or any electronegative element or the removal or an electropositive element.
2. Reduction is a process that involves the addition of hydrogen or any electropositive element or the removal of oxygen or any electronegative element.
3. Here we have a reaction
4. $\underset{\mathrm{Ferrous}\mathrm{oxide}}{{\mathrm{Fe}}_2{\mathrm{O}}_3}+\underset{\mathrm{Aluminum}}{2\mathrm{Al}}\to \underset{\mathrm{Iron}}{2\mathrm{Fe}}+\underset{\mathrm{Aluminum}\mathrm{Oxide}}{{\mathrm{Al}}_2{\mathrm{O}}_3}$

Oxidation Half reaction:

1. $2\mathrm{Al}\to {\mathrm{Al}}_2{\mathrm{O}}_3$
2. The oxidation number of aluminum ($\mathrm{Al}$) increases from zero to three and it involves the addition of oxygen in the reaction.
3. So the oxidation occurs in $\mathrm{Al}$.
4. Oxidizing agent: An oxidizing agent is a substance in a redox reaction which accepts or gains electrons or tendency to add oxygen atom.
5. So, ${\mathrm{Fe}}_2{\mathrm{O}}_3$ is oxidizing agent.

Reduction Half reaction:

1. ${\mathrm{Fe}}_2{\mathrm{O}}_3\to \mathrm{Fe}$
2. Hence, ${\mathrm{Fe}}_2{\mathrm{O}}_3$ is reduced to $\mathrm{Fe}$ because of removal of oxygen in ${\mathrm{Fe}}_2{\mathrm{O}}_3$ to adding in $\mathrm{Al}$.
3. Reducing agent: A reducing agent is a chemical species that accepts hydrogen or tendency to remove oxygen from elements
4. Aluminium $\mathrm{Al}$ acts as the reducing agent.

Therefore, Oxidizing agent: ${\mathrm{Fe}}_2{\mathrm{O}}_3$, Oxidation: $\mathrm{Al}$ , Reducing agent: $\mathrm{Al}$ , Reduction: ${\mathrm{Fe}}_2{\mathrm{O}}_3$