Question

What is a thermite reaction? Explain with the help of an equation. State one use of this reaction.

Answer 1

A thermite reaction is a reaction in which a metal oxide is reduced by using aluminium as the reducing agent. It is generally exothermic in nature, wherein a large amount of heat is liberated. Due to this heat, the metals produced are in the molten state.
An example of thermite reaction is the reduction of iron (III) oxide by using aluminium powder

$\underset{\mathrm{Iron}\left(\mathrm{III}\right)\mathrm{oxide}}{{\mathrm{Fe}}_2{\mathrm{O}}_3\left(s\right)}+\underset{\mathrm{Aluminium}\mathrm{powder}}{2\mathrm{Al}\left(s\right)}\to \underset{}{\underset{\mathrm{Iron}}{2\mathrm{Fe}\left(l\right)}+\underset{\mathrm{Aluminium}\mathrm{oxide}}{{\mathrm{Al}}_2{\mathrm{O}}_3\left(s\right)}+\mathrm{Heat}}$

Iron metal is produced when a mixture of iron (III) oxide and aluminium powder is ignited with a magnesium ribbon. The iron, so obtained, is in the molten state due to the large amount of heat liberated in the process. This is used to weld broken pieces of iron.

The above reaction is widely used in thermite welding to join broken pieces of iron.