Aluminium - ₁₃Al: reactions of elements

Reaction of aluminium with air

Aluminium is a silvery white metal. The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aulumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack. Aluminium will burn in oxygen with a brilliant white flame to form the trioxide alumnium(III) oxide, Al₂O₃.

4Al(s) + 3O₂(l) → 2Al₂O₃(s)

Reaction of aluminium with water

Aluminium is a silvery white metal. The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aulumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack, even by water.

Reaction of aluminium with the halogens

Aluminium metal reacts vigorously with all the halogens to form aluminium halides. So, it reacts with chlorine, Cl₂, bromine, I₂, and iodine, I₂, to form respectively aluminium(III) chloride, AlCl₃, aluminium(III) bromide, AlBr₃, and aluminium(III) iodide, AlI₃.

2Al(s) + 3Cl₂(l) → 2AlCl₃(s)

2Al(s) + 3Br₂(l) → Al₂Br₆(s)

2Al(s) + 3I₂(l) → Al₂I₆(s)

Reaction of aluminium with acids

Aluminium metal dissolves readily in dilute sulphuric acid to form solutions containing the aquated Al(III) ion together with hydrogen gas, H₂. The corresponding reactions with dilute hydrochloric acid also give the aquated Al(III) ion. Concentrated nitric acid passivates aluminium metal.

2Al(s) + 3H₂SO₄(aq) → 2Al³⁺(aq) + 2SO₄^2-(aq) + 3H₂(g)

2Al(s) + 6HCl(aq) → 2Al³⁺(aq) + 6Cl^-(aq) + 3H₂(g)

Reaction of aluminium with bases

Aluminium dissolves in sodium hydroxide with the evolution of hydrogen gas, H₂, and the formation of aluminates of the type [Al(OH)₄]^-.

2Al(s) + 2NaOH(aq) + 6H₂O → 2Na⁺(aq) + 2[Al(OH)₄]^- + 3H₂(g)