The compound used as common salt is:

1. sodium chloride
2. calcium chloride
3. sodium oxide
4. hydrogen chloride

Sand is a compound of:

1. silicon and nitrogen
2. silicon and oxygen
3. oxygen and sulphur
4. none of the above

The molecular formula of ammonia is:

1. NO
2. NH₃
3. NO₂
4. N₂O

The combining power of magnesium and oxygen is the same, i.e. 2. What will be the molecular formula of magnesium oxide ?

1. Mg₂O₂
2. MgO₂
3. Mg₂O
4. MgO