Write reactions to justify amphoteric nature of aluminium.
A substance is called amphoteric if it displays both characteristics of acids and bases. Aluminium dissolves in both acids and bases, showing amphoteric behaviour.
(i) 2Al(s) + 6HCl(aq) → 2Al3 + (aq) + 6Cl−(aq) + 3H2(g)
(ii) 2Al(s) + 2NaOH(aq) + 6H2O(l) → 2Na + [Al(OH)4]−(aq) + 3H2(g)