Question

Does iron nail rust when it covered with cotton. why?

Answer 1

Iron and steel rust when they come into contact with water and oxygen. They rust faster in salty water or acid rain. Aluminium, on the other hand, does not corrode easily, because its surface is protected by a layer of aluminium oxide.

The iron nail which is covered with cotton will not rust as the layer of cotton will prevent the moisture and oxygen from reaching the iron nail.