Question

Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.

Answer 1

The term Rusting involves slow oxidation of iron in presence of air and moisture which results in the formation of rust i.e. hydrated iron [III] oxide.

THE OXIDATION REACTION

Rusting of Iron

Iron + Oxygen → Iron [III] oxide   Rust Hydrated iron [III] oxide

\[\ce{4Fe + 3O2 -> 2Fe2O3->[X H2O][moisture] Fe2O3.x H2O}\]

Iron when exposed to the atmosphere slowly reacts with the oxygen of the air, in the presence of moisture forming a brown coating called ‘rust’ on its surface. Rusting corrodes iron and reduces its structural strength.