Question

Explain rusting, reaction involved, and at least three methods to prevent it. (5 Marks)

Answer 1

Dear student,
Rusting is a type of corrosion which occur on the surface of iron material, when its in contact with atmospheric oxygen. The aerial oxidation of iron produces iron oxide which is called rust. Formula of rust is Fe₂O₃. x H₂O
Rusting is an electrochemical process .When iron is in contact with water and oxygen or any other strong oxidants or acids it rusts .Rusting of iron takes place due to the interaction between oxygen and water in air. When this interaction takes places on iron, a reddish brown substance is deposited on iron and that is rust ( Fe ₂ O ₃ .xH ₂ O).

In other words, Corrosion of Iron in the presence of oxygen and air leads to formation of brown solid known as rust. This process is called rusting due to formation of rust.

4 Fe + 3 O₂ + 2x H₂O → 2 Fe₂O₃.xH₂O
Rusting can be prevented by

• by painting
• by galvanisation
• By oiling or greasing

Regards