Question

13 You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels

Answer 1

Lemon juice contains citric acid and tamarind contains tartaric acid. These adds react with basic layer of copper carbonate on the surface to form soluble salts which are easily removed and surface shines.

Answer 2

Copper when exposed to atmosphere forms a layer of hydrated oxide ( also called, rust ) which is basic in nature.lemon or tamarind juice contains acid..

So, to remove the oxide layer copper vessels are cleaned with lemon or tamarind and hence, they regain they lustre