Question

A tarnished copper vessel begins to shine again when rubbed with lemon.Why?

Answer 1

copper get tarnished when exposed to air. it reacts with air (moisture) to form copper hydroxide and form a green layer due to corrosion and get tarnished. this is basically basic in nature.

lemon is acidic in nature and when rubbed against the tarnished copper vessel, it reacts with it and form salt. Salt can be washed away with water and we can get back the shiny copper vessel back.

that's why, a tarnished copper vessel begins to shine again when rubbed with lemon.

Answer 2

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It is because tarnished copper vessel has a layer of copper oxide which is basic in nature. Lemon have citric acid. A reaction between acid & base results to form salt which can be easily washed out.Due to this tarnished copper vessel begins to shine again when rubbed with lemon.

hope it helps ☺️