Question

copper and brass vessel are cleaned with lemon​

Answer 1

Answer:

copper and brass vessel are cleaned with lemon to give the surface of the copper vessel it's characteristics lusture

Answer 2

Answer:

The citric acid present in the lemon or tamarind neutralises the basis copper carbonate and dissolves the layer. That is why, tarnished copper vessels are cleaned with lemon or tamarind juice to give the surface of the copper vessel its characteristic lustre.