Question

Consider the dipole moments of $NH_3$ and $NF_3$.Which of the following is correct ?

• A. Dipole moment of $NH_3$ is equal to that of $NH_3$
• B. Dipole moment of $NH_3$ is equal in magnitude but opposite in sign to that of $NH_3$
• C. Dipole moment of $NH_3$ is more than that of $NH_3$
• D. Dipole moment of $NH_3$ is more than that of $NF_3$

Answer 1

Answer: (D)

Both $NH_3$ and $NF_3$ have pyramidal structures Electronegativity of N, H and F is in the order F > N > H.
Due to lone pair and polarity of N-H and N-F bonds the dipole moment of $NH_3$ is much more than that of $NF_3$