Answer 1

In thermite reaction, iron oxide reacts with aluminium to produce molten iron. It is an exothermic process

The following reaction of iron oxide with aluminium as:
\[\ce{Fe2O3(s) + 2 Al (s)-> 2Fe (l) + Al2O3(s) + heat}\]

This is used to join railway tracks or cracked machine parts because the amount of heat evolved is so large that the metal is produced in the molten state.