Question

Give reason why tarnished copper vessel begins to shine when rubbed with lemon

Answer 1

tarnished copper vessel begins to shine when rubbed with lemon because the tarnishing on the surface of copper vessels is due to the formation of a basic compound that is basic copper carbonate CuSO4.(CuOH)2.

On rubbing with lemon the basic compound gets neutralized as lemon juice is an acid and therefore the surface of copper vessels shine.