Question

Rusting of iron is an example of:
(A) Reduction
(B) Ionization
(C) Oxidation
(D) Dissociation

Answer 1

Hint: Rusting of iron is a corrosion process. Rusting occurs when iron comes in contact with oxygen due to moisture in the atmosphere of water. It leads to the formation of a brown coloured substance which is an oxide of iron known as rust.

Complete step by step complete:
To answer this question, let us understand the meaning of the terms mentioned to us.
Oxidation is the loss of electrons and thus forms a positive species or if the starting reactant is neutral, it forms a neutral species. The reduction is the opposite of oxidation as it is the gain of electrons.
Ionisation is the process by which atom or a molecule gains or loses an electron and obtains a negative or a positive charge.
Dissociation is a process of breaking a single compound into two or more different products.
Now, let us discuss rusting of iron -
Rusting of iron- Rusting of iron is a chemical change which takes place in a long period of time. Rust is formed when the iron is exposed to an environment containing moisture. The oxygen present in the environment undergoes a redox reaction with the iron in a water-containing environment forming iron oxide which is commonly known as rust. Rust is a mixture of iron oxides formed on iron objects. Formation of rust takes a longer time and is not an immediate reaction.
The Fe(III) ions from an insoluble hydroxide which is known as rust-
\[2F{{e}^{3+}}+4{{H}_{2}}O(l)\to F{{e}_{2}}{{O}_{3}}{{H}_{2}}O(s)+6{{H}^{+}}(aq)\]
We can see from the above reaction that oxygen acts as an oxidising agent and iron acts as a reducing agent. Oxygen gains electrons and is reduced to hydroxide ion and Iron atoms lose electrons to form iron (II) hydroxide. Iron (II) hydroxide is further oxidised to form hydrated iron (III) oxide.
We can understand from the above discussion that rusting is a redox process therefore it is an example of oxidation as well as reduction.

Therefore, the correct answers are options [A] reduction and [C] oxidation

Note: Rusting of iron is basically corrosion of iron. Rusting is an irreversible process i.e. we cannot get back the pure iron from the oxide again. There are certain measures that can be taken to prevent rusting of iron. Generally, applying a layer of paint is adequate to prevent rusting however we can also cover the metal surface by a coating of zinc and this method is termed as galvanisation.