Question

Write the complete chemical reaction of rusting of iron.

Answer 1

Hint: Iron metal is one of the most useful metals due to the wide range of its applications in various products. It is relatively strong, lightweight and malleable (which means that it can easily be converted into sheets). However, if iron is not mixed with other metals then in its pure state it is quite susceptible to rusting. Due to the presence of oxygen and moisture in air, iron undergoes rusting and forms iron oxide.

Complete step by step answer:
Iron as well as its alloys rust because of a chemical reaction called oxidation. Due to the presence of oxygen and moisture in air iron undergoes rusting. The balanced chemical reaction for rusting of iron can be written as:
\[2F{e^{2 + }}(aq) + \dfrac{1}{2}{O_2}(g) + 2{H_2}O(l) \to F{e_2}{O_3}(s) + 4{H^ + }\]
\[F{e_2}{O_3}(s) + x{H_2}O \to F{e_2}{O_3}.x{H_2}O\]
Iron reacts with water and oxygen to form hydrated iron (III) oxide which we can see in the form of a red colored coating called rust. Surface rust is flaky in texture and it gives no protection to underlying iron. It is a specific term given to corrosion of iron. The main catalyst for this process is water as it can penetrate microscopic cracks in the metal. The hydrogen atoms present in water can further cause formation of acids which can further enhance this process. The presence of salt further enhances the process due to electrochemical reactions.

Note: Rusting of iron can be prevented by galvanization, painting, coating the surface with some other material and humidity control at the place where iron is stored.
Lower \[pH\] fastens rusting of iron whereas higher \[pH\] inhibits this reaction.
Some alloys of iron like stainless steel are resistant to rust due to the presence of some coating on them.