Question

Give reasons for the following:

The reaction of Iron (III) oxide$\left[{\mathrm{Fe}}_2{\mathrm{O}}_3\right]$ with heated Aluminium is used to join cracked machine parts.

Answer 1

Reaction between Iron(III) oxide and Aluminium:

• The reaction taking place between ${\mathrm{Fe}}_2{\mathrm{O}}_3$ and Aluminium ($\mathrm{Al}$)is a thermite reaction.
• This is an exothermic reaction, which generates a great amount of heat and results in the formation of molten iron metal, which is used to join the rails.
• The reaction proceeds as follows:

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

Thus, The reaction of iron (III) oxide$\left[{\mathrm{Fe}}_2{\mathrm{O}}_3\right]$ with heated aluminium is used to join cracked machine parts.