Q. Which of the following has maximum dipole moment?
CMC MedicalCMC Medical 2007
Solution:
Electronegativity difference between $ N(3.0) $ and $ Cl\,(3.0) $ is zero and hence $ N-Cl $ bonds are non-polar. As a result, the overall dipole moment of $ NC{{l}_{3}} $ molecule and its direction is just the dipole moment of the lone pair of electrons.
On the other hand, $ N-Br\,(3.0-2.8), $ $ N-I\,(3.0-2.5) $ and $ N-H\,(3.0-2.1) $ are polar and hence contribute towards the overall dipole moment of the respective molecules. Since the EN difference is highest in case of $ N-H $ bonds, therefore, $ N{{H}_{3}} $ has the highest dipole moment.
