Question

4.In a construction site, iron rods are left in the open air for some time, it
acquires a film of brownish substance.
d. Write two preventing methods of this change

Answer 1

1-Paint the iron to cover it with a layer which will protect it from getting oxidized
2-dip the iron in oil or greese which will end the direct contact of iron from oxygen.

Answer 2

¤ by Galvanization ( coating the surface with an external layer of metallic zinc)
¤ Organic coatings ( such as applying paint )