Question

Chandi Ke Upar Kali Parat chalana Kiska udaharan hai​

Answer 1

Answer:

Black coating on silver coins is due to silver sulphide(Ag2s). 2 Ag(s) + H2S(g) ----- Ag2S(s) + H2(g). Green Coating on copper coins is due to copper carbonate and copper hydroxide.

Explanation:

Answer 2

Answer:

This is an example of rusting