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Rusting of iron is catalyzed by:
(A)- ${{H}^{+}}$ ions
(B)- Dissolved $C{{O}_{2}}$ in water
(C)- ${{O}_{2}}$
(D)- Impurities present

Last updated date: 25th Jun 2024
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Hint: When we leave a piece of iron in the open for a while, a film of brownish substance gets deposited on its surface called rust. Rusting occurs when iron is exposed to oxygen in air and water or water vapor.

Complete step by step answer:
> Rust is Iron Oxide. Hydrated ferric oxide is $F{{e}_{3}}{{O}_{2}}.x{{H}_{2}}O$. There are two different types of valency of Iron (Fe) +2 and +3. So two types of Fe positive ions are seen.
 > Rusting or Corrosion is a Redox Reaction where Oxidation and Reduction take place simultaneously. Other metals form layers of oxides that prevent the further from corrosion but Iron slowly and steadily disintegrates because of rusting.
> The rusting process begins when iron reacts with oxygen in the presence of water, saltwater, acids, or other harsh chemicals.
> When iron comes in contact with water and oxygen, then a film of iron oxide develops. This is known as formation of iron oxide or rusting.
But catalyst means any substance which makes the reaction faster. Any substance which will make rusting of iron faster will catalyze the reaction.
> Rusting is catalyzed by acidic medium (i.e. presence of ${{H}^{+}}$ ions).
So, ${{H}^{+}}$ ions furnished in the solution will catalyze the rusting of iron.
Hence, the correct answer is option (A)

Additional Information: As the iron oxide flakes off the metal surface, it exposes fresh iron molecules, which continue the reaction process. Eventually, large areas of rust form that may cause the entire metal structure to disintegrate.

Notes: Rusting is a demerit but we have many procedures to prevent iron from rusting. The most important of which is galvanization: the process of applying a protective layer of zinc on iron done by dipping the metal to be protected in hot, molten zinc or by the process of electroplating. A layer of acrylic, vinyl, epoxy or other substances will also prevent moisture from reaching the metal, thereby preventing rust.