Question

Which of the following has a maximum dipole moment?

• A. NH₃
• B. NF₃
• C. PF₅
• D. PCL₅

Answer 1

The Correct Option is A

The question asks which among the given compounds has the maximum dipole moment. To answer this question, we need to understand the concept of dipole moment and the molecular structures of the given compounds.

Dipole Moment: Dipole moment is a measure of the separation of positive and negative charges in a molecule. It is a vector quantity, which means it has both magnitude and direction. Dipole moment is determined by the following formula:

\mu = q \cdot d

where \mu is the dipole moment, q is the charge, and d is the distance between the charges.

The dipole moment depends on the difference in electronegativity between atoms and the geometry of the molecule.

Analyzing the Options:

• NH₃ (Ammonia): NH₃ has a pyramidal structure with a lone pair of electrons on nitrogen, which results in a net dipole moment. The highly electronegative nitrogen atom pulls electron density towards itself, creating a significant dipole moment.
• NF₃ (Nitrogen Trifluoride): NF₃ also has a pyramidal structure similar to NH₃, but the electronegativity difference between nitrogen and fluorine is less significant because fluorine atoms pull the electrons away from the nitrogen. This results in a lower dipole moment compared to NH₃.
• PF₅ (Phosphorus Pentafluoride): PF₅ has a trigonal bipyramidal arrangement, leading to a symmetrical distribution of electrons, which cancels out the dipole moments and results in an overall dipole moment of zero.
• PCl₅ (Phosphorus Pentachloride): Similar to PF₅, PCl₅ has a symmetric trigonal bipyramidal structure, resulting in no net dipole moment.

Conclusion: Among the given options, NH₃ has the highest dipole moment due to its asymmetric pyramidal structure and the presence of a lone pair on nitrogen, combined with a significant electronegativity difference between nitrogen and hydrogen.

Therefore, the compound with the maximum dipole moment is NH₃.