Question

why magnesium ribbon is rubbed with Sandpaper before burning​

Answer 1

• Magnesium react with oxygen to form magnesium oxide, which does not burn. So to remove this oxide layer Magnesium ribbon is cleaned with sand paper before burning.

• Magnesium 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 is quite stable and prevents further reaction of magnesium with oxygen the magnesium ribbon is cleaned by sand paper for removing this layer so that the underlying metal can be exposed to air.

Answer 2

answer : Since Magnesium is an reactive metal in the reactivity series, when it is exposed to oxygen it will form metal oxides. For example, when oxygen is mixed with one of these metals for an extended period of time, you will see rust form and a brownish color coat over it as a tint. With Magnesium, what will happen if exposed to oxygen for too long is create a white coating on the outside of it which will impede and effect the burning process.

Thus, when sanded with sand paper, we are able to remove this extra layer that is impeding the burning, so that it can burn as if it weren't exposed to years of oxygen.