Question

Why is zinc coating used in iron bridges?

• A. Because zinc is cheaper than iron.
• B. Because it prevents corrosion.
• C. Because zinc is better conductor of heat.
• D. Because zinc is less reactive than iron.

Answer 1

The correct option is B

Because it prevents corrosion.

Zinc forms a coating of a corrosion-resistant layer which prevents corrosive substances from reaching the more delicate part of the metal, in this case, iron. Moreover, even if the coating is scratched, the exposed metal will still be protected by the remaining zinc.