Question

How do you determine an oxidizing agent within a reaction?

Answer 1

The one whose FORMAL `"oxidation number"` is reduced in a chemical reaction is the `"oxidizing agent"`.

Explanation:

Strong oxidizing agents include `F_2` and `O_2`, `MnO_4^(-)`, and `Cr_2O_7^(2-)`. The oxidation numbers of the central atom in these species are `0`, `VII+`, and `VI+` respectively.

During the oxidation, these reagents are conceived to ACCEPT electrons from the species that is oxidized, and this transfer may be formalized in the following reactions:

`1/2F_2 +e^(-) rarr F^(-)`

`1/2O_2 +2e^(-) rarr O^(2-)`;

`MnO_4^(-) + 8H^(+) + 5e^(-) rarr Mn^(2+) + 4H_2O`;

`Cr_2O_7^(2-) + 14H^(+) + 6e^(-) rarr 2Cr^(3+) + 7H_2O`

Are charge and mass balanced here? If not, they should be. Difluorine, dioxygen, permanganate, and dichromate, are all potent oxidizing agents, and their function as oxidizing agents results in reduced metal ions.

See here for other examples of redox reactions.