Question

Chemically rust is:
a.) Hydrated ferrous oxide
b.) Hydrated ferric oxide
c.) Only ferric oxide
d.) None of these

Answer 1

Hint: The compound that is the answer to this question has another name that we call “Hydrated Ferric(III) oxide”. Now you should try to figure out the correct answer.

Complete step by step answer:
Rust is a reddish-brown oxide formed by the reaction of iron and oxygen in the presence of water or air moisture. The formation of rust is a chemical process.
Several forms of rust can be distinguished both visually and by spectroscopy.
Rust consists of hydrated iron(III) oxides $\text{F}{{\text{e}}_{2}}{{\text{O}}_{3}}\text{ }.\text{ n}{{\text{H}}_{2}}\text{O}$.
It occurs in moist air and in water. As we already discussed rust requires three chemicals in order to form: iron, oxygen, and water.
$\text{4 Fe + 3 }{{\text{O}}_{2}}\text{ + 2 }{{\text{H}}_{2}}\text{O }\to \text{ 2 F}{{\text{e}}_{2}}{{\text{O}}_{3}}\text{ }.\text{ }{{\text{H}}_{2}}\text{O}$
Hydrated iron(III) oxide is also known as hydrated ferric oxide because here oxidation state of iron is +3.
Due to the process of rusting the iron starts to degrade and the iron becomes useless and weak.
So, the correct answer is “Option B”.

Note: We should know that rust is brittle, fragile, progressive, and weakens iron and steel.
- For the protection of iron and its alloys from rust, the surface needs to be separated from air and water. Coatings can be applied to iron.
- The stainless steel contains chromium, which forms an oxide. The difference is that chromium oxide does not flake away, so it forms a protective layer on the steel.