Pick up the correct statement.

• Correct answer
  A

  Dipole moment of ammonia is due to orbital dipole and resultant diapole in same direction.
• B

  $\mathrm{O}_2, \mathrm{H}_2$ shown bond diapole due to polarisation.
• C

  Dipole moment is scalar quantity.
• D

  In $\mathrm{BF}_3$ bond dicopoles are zero but dipole moment is higher.

Solution

Option (a) is the correct option. In ammonia,
As, nitrogen is more electronegative than hydrogen, the resultant dipole moment adds up in the same direction. Dipole moment is a vector quantity. $\mathrm{O}_2$ and $\mathrm{H}_2$ are homoatomic molecules thus, show no dipole.

Hence, the correct answer is option: 'A'.