Question

Why should magnesium ribbon be cleaned with sand paper before burning?

Answer 1

Answer:

A magnesium ribbon be cleaned before burning in air to avoid the layer of magnesium oxide which form due to the presence of oxygen and chemical equation is :-

Mg + O2 ------> MgO2

So when we rub magnesium ribbon then the oxide layer get seprated and we got fresh magnesium

Explanation:

hope it helps

Answer 2

Answer :

Magnesium is a highly reactive metal. When exposed to air for a long time it gets coated with the layer of oxide which is physically and mentally stable and therefore, partly masks the reactivity of magnesium. The oxide coating does not burn when a flame is brought in contact with the metal. Therefore, the surface should be cleaned, with a sandpaper before burning the magnesium ribbon in air.