4.23. Which out of NH₃ and NF₃ has higher dipole moment and why?         

4.23. The dipole moment of NH₃ (1.47D) is higher than the dipole moment of NF₃ (0.24D), even though the molecular geometry is pyramidal for both the molecules. In each molecule, N atom has one lone pair. F is more electronegative than H and N? F bond is more polar than N? H bond. Hence, NF₃? is expected to have much larger dipole moment than NH₃. However, reverse is true. In case of ammonia, the direction of the lone pair dipole moment and the bond pair dipole moment is same whereas in case of NF₃, it is opposite. Thus, in ammonia molecule, individual dipole moment vectors add whereas in NF₃, they cancel each other.

<p><strong>4.23.&nbsp;</strong>The dipole moment of NH₃ (1.47D) is higher than the dipole moment of NF₃ (0.24D), even though the molecular geometry is pyramidal for both the molecules. In each molecule, N atom has one lone pair. F is more electronegative than H and N? F bond is more polar than N? H bond. Hence, NF₃? is expected to have much larger dipole moment than NH₃. However, reverse is true. In case of ammonia, the direction of the lone pair dipole moment and the bond pair dipole moment is same whereas in case of NF₃, it is opposite. Thus, in ammonia molecule, individual dipole moment vectors add whereas in NF₃, they cancel each other.</p><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1741770982phpfEKJBR_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1741770982phpfEKJBR.jpeg" alt="" width="368" height="153"></picture></div></div>

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