Question

Surface of some metals lose their brightness when kept in air for a long time.Why??



........plzzz answer...

Answer 1

Because of corrosion, as the reaction of air and water with metal gradually eat it up and metal loses its Lustre.
Hope this will be helpful :)

Answer 2

due to high reactivity property it reacts with air which cause corrosion and loss in the property of surface of metals in air it reacts with moisture