tell me in terms of reduction potential of zinc and reduction potential of iron
Corrosion of iron involves oxidation of iron to ferrous ions. Since zinc is above iron in electrochemical series (read reactivity) hence coating of iron with zinc (known as Galvanizing) protects iron as now it is the zinc that is oxidized in place of iron. The process is know as Galvanization
In the electrochemical series the metal zinc has high reactivity than iron to react so when iron is exposed to air instead of reacting with iron the atmospheric air react with Zinc of being its high reactivity so some zinc is added with iron materials.
