Concept:A molecule has a zero dipole moment when it possesses perfect structural symmetry and lacks distorting lone pairs on the central atom.
Formula:$$ \sum \vec{\mu} = 0 \quad (\text{Trigonal Planar}) $$
Solution:- Boron trifluoride (\( \text{BF}_3 \)) has a central Boron atom with exactly 3 bonding pairs and 0 lone pairs.
- This gives it a flat, perfectly symmetrical trigonal planar shape with 120° angles.
- The highly polar pulls of the three Fluorine atoms perfectly cancel each other out in 2D space, leaving the molecule non-polar overall.
Why other options are incorrect:- Option B, Option C, Option D: All of these central atoms (N, O) possess lone pairs, distorting the molecular symmetry into pyramidal or bent shapes, meaning the bond dipoles cannot cancel out.
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