Question

why should mg ribbon be cleaned before burning in air

Answer 1

Hii There!!!

Magnesium ribbon should be cleaned by using sand paper before burning in air to remove thin magnisum carbonate layer. Since, magnesium ribbon forms an inert layer of magnesium carbonate and this layer is very unreactive.
Hence, it needs to be cleaned.


Hope it helps

Answer 2

♤ When Magnesium ribbon is exposed in the atmosphere it form a layer of magnesium oxide on its surface.

♤ This layer of magnesium oxide is stable compound to prevent further reaction of magnesium with oxygen.

♤ Hence, it should be cleaned before burning in air to remove this layer so that the metal can be exposed to air properly.