Why acid causes corrosion of metal ?

Why acid causes corrosion of metal ?
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Answer :

We heard about acid. I know it dissolves other solids. Many times some professional thieves melt the lock with acid without breaking the lock for theft. So how did the acid get such horrible properties ? Acids always contain hydrogen. Such as: HCI- hydrochloric acid , H 2 SO 4 - sulfuric acid. Most metals are more active than hydrogen atoms. This means that the metal atom removes the hydrogen atom from the acid and replaces the hydrogen itself. As a result, the number of atoms in a piece of metal decreases. This is why exposure to acid actually causes metal to decay.
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