Question

Give reasons for the following:

a) Iron is used to construct bridges and houses.

b) Iron sheets are galvanized before use.

Answer 1

a)Iron is a strong hard and tough metal, hence it can resist the high load, stress and strain. Also, it is capable to lift a load of different things at the same time. Hence it isused to construct bridges .


b)

The iron sheet is galvanized with zinc to prevent it from rusting. The most external layer is all zinc, but successive layers are a mixture of zinc and iron, with an interior of pure sheet. These multiple layers are responsible for the amazing property of the metal to withstand corrosion-inducing circumstances, such as saltwater or moisture.

Zinc also protects the steel by acting as a sacrificial layer. The rust does take hold on the surface of galvanized iron sheet; the zinc will get corroded first. This allows the zinc to prevent rust from reaching the iron sheet.