Question

A turnished surface of copper vessel can be cleand up with lemon. Why this sour substance is effective in cleaning the metal vessels

Answer 1

turnished surface of copper vessel can be cleand up with lemon because the turnishing on the surface of copper vessels is due to the formation of a basic compound that is basic copper carbonate (CuSO4.(CuOH)2).

This basic compound gets neutralized on cleaning with a sour substance (acid).