Rusting can be prevented by covering iron in zinc; this method is called

• A. Galvanisation
• B. Coating
• C. Electroplating
• D. Alloying

Answer: (A)

The main idea is protecting iron by sacrificial protection: a more reactive metal is used to corrode in place of iron. Zinc is more reactive than iron, so when a zinc coating covers iron, zinc preferentially oxidizes in the presence of air and water. This means the zinc layer corrodes instead of the iron, forming zinc oxide/hydroxide and a barrier that keeps the iron underneath from rusting. Even if the coating is scratched, the exposed zinc nearby continues to protect the iron, extending the life of the metal. This specific protective method is called galvanisation. Other options are broader or describe different processes (coating in general, electroplating uses electricity to deposit metal, alloying changes the material itself rather than adding a protective outer layer), so galvanisation is the correct term.