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Metals and Non-metals
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.
The copper vessels are tarnished due to the reaction of copper with moist air to form copper hydroxide and copper carbonate.
Cu + H2O + CO2 + O2 → Cu(OH)3 + CuCO3
Moist Air Green coating on copper
Lemon contains citric acid while tamarind juice contains tartaric acid. These acids dissolve the copper hydroxide and copper carbonate present on the tarnished copper and shiny red-brown appearance of copper occurs.
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