Metal M reacts with oxygen to form metallic oxide MO. This oxide reacts with moisture and carbon dioxide of the atmosphere to form a basic carbonate. Metal M can prevent rusting of iron. Identify metal M.

Explanation

Since the metal form an oxide MO, the metal is divalent. Since it forms a basic carbonate when exposed to moisture and carbon dioxide, therefore it must be copper.
`2Cu +underset("From moist air")underbrace(CO_(2)+O_(2) +H_(2)O)to underset("Basic copper carbonate")(CuCO_(3).Cu(OH)_(2)) `
since copper is less electropositive than iron, if iron is covered with copper it can prevent rusting.