Question

Why why why should a magnesium ribbon be cleaned before burning in air?

Answer 1

Magnesium ribbon is a very reactive metal. When stored it reacts with oxygen to form a layer of magnesium oxide on its surface. This layer of magnesium oxide being a stable compound prevents further reaction of magnesium with oxygen. The magnesium is cleaned before burning in air to remove this layer so that the metal can be exposed to air properly.

hope it helps you

Answer 2

Magnesium ribbon reacts with oxygen in the air to make magnesium oxide which doesn't allow the ribbon to burn in the air. btw have you just passed 9th class ? and went to 10th