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

The reduction of a metal oxide to form metal by using aluminium powder as a reducing agent is called a thermite reaction.

A mixture of Iron (III) oxide and aluminium powder is ignited with a burning magnesium ribbon. Aluminium reduces iron oxide to produce iron metal with the evolution of a lot of heat. Due to this heat, iron metal is produced in the molten state. This molten iron is then poured between the broken iron pieces to weld them

Fe2O3(s) + 2Al(s) → 2Fe(l) + Al2O3(s) + Heat