Electrochemistry

Rusting of iron is envisaged as setting up of electrochemical cell on the surface of iron object.

Dissolved acidic oxides \(\mathrm{SO}_2, \mathrm{NO}_2\) in water act as catalyst in the process of rusting.

Coating of iron surface by tin prevents rusting, even if the tin coating is peeling off.

When \(\mathrm{pH}\) lies above 9 or 10, rusting of iron does not take place.