Question

Fill in the following blanks with suitable words
(a) Magnesium liberates ............... gas on reacting with hot boiling water.
(b) The white powder formed when magnesium ribbon burns in oxygen is of ....................
(c) Ordinary aluminium strips are not attacked by water because of the presence of a layer of ................. on the surface of aluminium.
(d) A metal having low melting point is ..................... but a non-metal having very high melting point is ..............
(e) Calcium is a ................. reactive metal than sodium.

Answer 1

Answer:

hydrogen

mgo2

oxygen

mercury

diamond

less

Answer 2

Explanation:

• (a) Hot water contains molecules of hydrogen and oxygen and so when magnesium reacts with hot boiling water, magnesium will form magnesium oxide. Thus the remaining hydrogen atoms will be liberated from the water molecules.

• (b) If magnesium ribbon is burnt in oxygen then it will tend to form magnesium oxide. And magnesium oxide is white in color . So white powder formed when magnesium ribbon burns in oxygen.
• (c) Aluminium strips are in continuous contact with atmospheric oxygen. So they will be forming aluminium oxide on the surface of strips. And this aluminium oxide prevents the attack of water on the surface. So ordinary aluminium strips are not attacked by water because of the presence of a layer of aluminium oxide on the surface of aluminium.
• (d) A metal having low melting point is sodium but a non-metal having very high melting point is Diamond.
• (e) Calcium has almost fully filled outermost shell and so it is less reactive metal. So calcium is a less reactive metal than sodium.