Molecule Having Maximum Dipole Moment

Question:
Which one of the following molecules has maximum dipole moment?

Correct Answer: NH₃

Explanation (Dipole Moment Concept)

Dipole moment depends on molecular geometry and vector addition of bond dipoles.

• CH₄: Tetrahedral and symmetrical → dipole moment = 0

• PF₅: Trigonal bipyramidal and symmetrical → dipole moment = 0

• NF₃: Pyramidal but bond dipoles oppose lone pair dipole → small dipole moment

• NH₃: Pyramidal and bond dipoles reinforce lone pair dipole → maximum dipole moment

Hence, the molecule with maximum dipole moment is NH₃.

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