What is a thermite reaction?

Explanation

The reduction of a metal oxide to form metal by using aluminium powder as a reducing agent is called a thermite reaction. The reaction is highly exothermic in which the metal produced is in its molten state.
This property is used in thermite welding for joining the. broken pieces of heavy iron objects like girders, railway tracks or cracked machine parts. This is done as follows: A mixture of iron (111) oxide and aluminium powder is ignited with a burning magnesium ribbon. Aluminium reduces iron oxide to produce iron metal with the evolution of lot of heat. Due to this heat, iron metal is produced in the molten state.
Iron is then poured betweenthe `underset("Iron (III)")(Fe_(2)O_(3)(s)) + underset("Aluminium")( 2A(s)) to underset("Aluminium power")(2Fe(I)) + underset("(in molten state)")(underset("Iron metal")(Al_(2)O_(3)))`
The molten iron is then poured between the broken iron pieces to weld them. This process is called aluminothermy or thermite welding.