Question

Chemically rust is
(a) Hydrated ferrous oxide
(b) hydrated ferric oxide
(c) only ferric oxide
(d) none of these
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Answer 1

(b) hydrated ferric oxide

Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances.[1] Rust consists of hydrated iron(III) oxides Fe2O3·nH2O and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3).

Answer 2

Chemically rust is Hydrated ferric oxide.

Among the given options, option (b) hydrated ferric oxide is correct.

All the given options (a) Hydrated ferrous oxide, (c) only ferric oxide, and (d) None of these are incorrect because the chemical formula of rust is hydrated iron (III) oxide, i.e., $Fe_2O_3.xH_2O$.

Explanation:

Rust formula :

• Rust is a hydrated ferric oxide (hydrated iron (III) oxide).

• The chemical formula of rust is $Fe_2O_3.xH_2O$.

Rusting :

• Rusting in iron is characterized by forming a layer of a red, flaky substance that readily turns into powder.

• In the presence of moisture, iron (Fe) combines with oxygen from the air to form a brown chemical substance called rust (iron oxide).

• Rusting is a part of rust and is a chemical process that forms a red coating on the surface of metals.

• Rust usually occurs on the surfaces of iron and its alloys.

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