Question

What is thermite reaction.How it is used to join the railway tracks or cracked machine parts.

Answer 1

Thermite reaction takes place in the presence of heat ( thermal condition) which helps in forming fused metals (metals in molten form) . This fused metals helps in join railway tracks or joining other broken metals .

Answer 2

Thermite reaction: The reduction of a metal oxide to form metal by using

aluminium powder as a reducing agent is called a thermite reaction.

It is an exothermic reaction in which a large amount of heat is evolved. This

reduction property of aluminium is used in thermite welding for joining the broken pieces of heavy iron objects like girders, railway tracks or cracked machine parts.

Example: A mixture of iron (III) oxide and aluminium powder is ignited with a burning magnesium ribbon. Aluminium reduces iron oxide to produce molten iron metal with the evolution of heat.

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

The molten iron produced is then poured between the broken iron pieces to weld them.