AIPMT PRELIMS 2006 Chemistry Dipole Moment MCQ Question
The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH₃ (1.5 D) is larger than that of NF₃ (0.2 D). This is because :
in NH₃ as well as in NF₃ the atomic dipole and bond dipole are in the same direction
in NH₃ the atomic dipole and bond dipole are in the same direction whereas in NF₃ these are in opposite directions
in NH₃ as well as NF₃ the atomic dipole and bond dipole are in opposite directions
in NH₃ the atomic dipole and bond dipole are in the opposite directions whereas in NF₃ these are in the same directions
Correct Answer
Detailed Explanation
In NH₃, the lone pair contributes to the dipole moment in the same direction as the N⁻H bonds, while in NF₃, the lone pair dipole opposes the N⁻F bond dipoles, reducing the overall dipole moment.
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