Why do we rub the magenesium ribbon before burning?

1.	Why do we rub the magenesium ribbon before burning?
Answer» Its because in contact with the atmosphere,magnesium present in the outer layer of the magnesium ribbon reacts with the atmospheric oxygen thus forming MgO.By rubbing it with a cloth,we remove the outer layer of MgO and thus there is only Mg now to be burned and that\'s what is needed for the experiment. Because it has protective layer of basic megnesium carbonate so we rubb the magnesium ribbon

Discussion