(a) Explain the term “corrosion” with an example. Write a chemical equation to show the process of corrosion of iron.
(b) What special name is given to the corrosion of iron?
(c) What type of chemical reaction is involved in the corrosion of iron?
(d) Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
(a) Corrosion is the process in which metals are eaten up gradually by the action of air, moisture or a chemical (such as an acid) on their surface. Rusting of iron metal is the most common form of corrosion.
During the corrosion of iron, iron metal is oxidised by the oxygen of air in the presence of water (moisture) to form hydrated iron oxide called rust.
4Fe + 3O2 + 2XH2O → 2Fe2O3.xH2O
Iron Oxygen Water Hydrated iron oxide(Rust)
(b) Rusting.
(c) Oxidation.
(d) Railings, car bodies and bridges.