Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because:

1. Standard reduction potentials: $E_{{\text{Zn}}^{2+}/\text{Zn}}^{\circ }=-0.76\text{V}$, $E_{{\text{Fe}}^{2+}/\text{Fe}}^{\circ }=-0.44\text{V}$.2. Zinc has a more negative reduction potential than iron, meaning it is more easily oxidized (more reactive).3. In galvanization, Zinc acts as a sacrificial anode. Even if the coating is scratched, Zinc will oxidize in preference to iron.4. Coating iron on Zinc would not work for protection because iron is less reactive and wouldn't provide cathodic protection.