Question

Compound X and aluminium are used to join railway tracks.

(a) Identify the compound X

(b) Name the reaction

(c) Write down its reaction.

Answer 1

• The reaction between the aluminum with the metal oxides, where aluminum acts as a reducing agent. The aluminum reduces the metal oxide most probably an iron (lll) oxide to produce ferrous and aluminum oxide. During the reaction, a large amount of energy is released.
• The reaction between the metal and metal oxide is exothermic and is also called a thermite reaction.
• Example- $\underset{\mathrm{Iron}\left(\mathrm{III}\right)\mathrm{oxide}}{{\mathrm{Fe}}_2{\mathrm{O}}_3}+\underset{\mathrm{Aluminum}}{\mathrm{Al}}\to \underset{\mathrm{Aluminum}\mathrm{oxide}}{{\mathrm{Al}}_2{\mathrm{O}}_3}+\underset{\mathrm{Iron}}{\mathrm{Fe}}$
• Here, Aluminium$\left(\mathrm{Al}\right)$ is more reactive than Iron$\left(\mathrm{Fe}\right)$ so it replaces iron from its oxide and forms aluminum oxide$\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)$ and Iron$\left(\mathrm{Fe}\right)$ with a lot of heat energy.

(a) Compound X is ${\mathrm{Fe}}_2{\mathrm{O}}_3$

(b) The involved reaction is a thermite reaction which is also called aluminothermy.

(c) ${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{Al}\to {\mathrm{Al}}_2{\mathrm{O}}_3+\mathrm{Fe}$