Question

Why must we mention the oxidation state of iron in iron oxide?

Answer 1

`Fe_2O_3` = Iron (III) Oxide
`FeO` = Iron (II) Oxide

Explanation:

`Fe_2O_3` = Iron (III) Oxide:
Explains that the oxidation state of Iron in this compound `Fe_2O_3` is `Fe^(3+)`

`FeO` = Iron (II) Oxide: Explains that the oxidation state of Iron in this compound `FeO` is `Fe^(2+)`

Both are two different compounds, with different physical as well as chemical properties therefore it is must to mention the oxidation state along with the compound name.