Give a reason: Aluminium is more reactive than iron. Yet there is a less corrosion of aluminium, when both are exposed to air.

Complete the following reaction with balanced chemical equation.

${\mathrm{Al}}_2{\mathrm{O}}_3\left(\mathrm{s}\right) + \mathrm{HCl}\left(\mathrm{aq}\right) \stackrel{}{\to }$

Complete the following reaction with a balanced chemical equation:

${\mathrm{Al}}_2{\mathrm{O}}_3\left(\mathrm{s}\right) + \mathrm{NaOH}\left(\mathrm{aq}\right) \stackrel{}{\to }$

Complete the following reaction with a balanced chemical equation.