Question

A metal when exposed to air forms black coating over it. Name the
process and the metal compound formed by the process.​

Answer 1

Answer :-

Corrosion is the formation of metal oxide when exposed to moist air.

hope it helps you

Answer 2

Answer:

rust of iron oxide. corrosion occurs in the presence of moisture. for example when an iron is exposed to moist air it reacts with oxygen to form rust (Fe2o3)