Question

Explain the following. Reactivity of aluminium decrease if it is dipped in nitric acid.

Answer 1

Reactivity of aluminium decrease if it is dipped in nitric acid.

1. Nitric acid is a corrosive mineral acid and a strong oxidizing agent.
2. When Aluminium is dipped in Nitric acid, it gets oxidized forming a oxide layer of Aluminium oxide, the layer of Aluminium oxide is unreactive thus, prevents further reaction of aluminium.

3.The overall reaction is:

$\underset{\mathrm{Aluminium}}{2\mathrm{Al}\left(\mathrm{s}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{6{\mathrm{HNO}}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Aluminium}\mathrm{oxide}}{{\mathrm{Al}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Nitrotro}\mathrm{dioxide}}{6{\mathrm{NO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

Nitric acid is a corrosive mineral acid on dipping Aluminium it forms a layer of oxide over it, thus, decreasing the reactivity of Aluminium.