Question

Give reasons why:a}Magnesium ribbion should be cleaned before burning in air b}Iron should be protected from moist air.

Answer 1

If exposed to oxygen and moisture in air, iron will rust or develop a reddish brown layer of hydrated iron oxide or rust that will damamge the iron.

Fe(s) + H2O(g) + O2(g) --- Fe2O3. n H2O (s

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.