Question

why should the magnesium ribbon be cleaned before burning in air​

Answer 1

Hey mate here is your answer.

Magnesium ribbon should be cleaned before burning in air.It is done to remove oxide layer present on the magnesium ribbon.

Answer 2

Magnesium ribbon is cleaned with sandpaper before burning in air because it reacts with oxygen and forms a white layer of magnesium oxide and this layer is unable to burn. And in order to remove this layer , we should clean it.

Hope helps