Zinc is used to protect iron from corrosion because zinc is

⚡ Electropositivity and Galvanization
→ The electropositivity of an element is the ability of the element to lose electrons.
→ Galvanization is the method employed to protect the rusting of the iron surface through a coat of zinc.
→ Zinc metal present on the surface of iron forms a thin protective layer of basic zinc carbonate due to the reaction between zinc, oxygen, CO₂, and moisture in the air.
→ The standard reduction potential of zinc is less than iron, meaning zinc is more reactive than iron. Hence, iron will not undergo corrosion.