alleryAmong the following, the molecule with a zero dipole moment despite polar bonds is:
AH₂O
BNH₃
CBF₃
DHF
Answer & Solution
Correct answer: C. BF₃
1. BF₃ is trigonal planar (sp² B, 0 lone pairs); the three B-F bond dipoles point at 120° to each other and CANCEL.
2. Net dipole moment = 0 despite each B-F bond being polar.
3. H₂O (bent), NH₃ (pyramidal) and HF (diatomic) all have non-zero net dipole moments.
_Source: syllabus Chem Ch 4 §4.2 Dipole Moments of Symmetric Molecules_
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