Which of the following statements is not correct about rusting of iron?
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.
