The term amphoteric describes a substance that can act as both an acid and a base.
Steel is an alloy and consists of more than one element (mainly iron and carbon), therefore steel is a mixture.
I’d say most likely air, oxygen, or carbon dioxide
meaning:An acid is a chemical substance, usually a liquid, which contains hydrogen and can react with other substances to form salts. Some acids burn or dissolve other substances that they come into contact with.
