Which of the following metals corrodes readily in moist air?

What is observed on the corrosion of $Fe$,$Cu$,and $Ag$ metals?

To protect iron against corrosion,the most durable metal plating on it is:

The protection of steel by chrome plating is due to

Iron rusts in moist air because of:

Iron pipes lying under acidic soil are often attached to blocks of magnesium for protection from rusting. Magnesium offers protection to iron against corrosion because it