Chemistry - Electrochemistry Question with Solution | TestHub

The standard reduction potential of zinc ($E_{{\text{Zn}}^{2+}/\text{Zn}}^{\circ }=-0.76\text{ V}$) is lower than that of iron ($E_{{\text{Fe}}^{2+}/\text{Fe}}^{\circ }=-0.44\text{ V}$).

Since iron has a higher reduction potential than zinc, it has a greater tendency to get reduced. When the galvanized sheet is scratched and both metals are exposed to the environment, an electrochemical cell is formed.

Zinc, having a higher oxidation potential, acts as the anode and undergoes oxidation preferentially. It supplies electrons to the iron, which acts as the cathode. This prevents the oxidation of iron, thereby protecting it from corrosion. This method of protection is known as cathodic protection.

Answer: Iron has a higher reduction potential than zinc, making iron the cathode.