Sour food should not be stored in copper vessels. What is the scientific reason?

Correct answer: Acids can react with copper to form harmful salts

The governing concept is the chemical reactivity of food acids with metals. Sour foods commonly contain acids such as acetic, citric, or lactic acid. During prolonged contact, these acids may react with copper or its surface compounds and introduce copper salts into the food. Some copper compounds are harmful in excessive amounts, so such storage is avoided. Option A is correct; the other statements contradict the acidic nature of sour foods or make unsupported claims.