Question

why should curd and sour substances not be kept and copper vessels​

Answer 1

Answer:

Curd and sour substances contain acids. Acids react with metals to produce salt and hydrogen gas. So, if such substances are kept in copper container, the acid will react and the container will be corroded.

Answer 2

Answer:

Curd and sour substances contain acids. Acids react with metals to produce salt and hydrogen gas. So, if such substances are kept in copper container, the acid will react and the container will be corroded.