AIIMS 2018 Chemistry Dipole Moment MCQ Question

Option C is correct because BF₃ is a nonpolar molecule with a symmetrical trigonal planar geometry, resulting in a net dipole moment of zero, while NH₃ has a significant dipole moment due to its pyramidal shape and the presence of a lone pair on nitrogen, which creates an asymmetrical distribution of electron density.

In option A, SO₂ has a greater dipole moment than H₂O due to its bent shape and larger electronegativity difference, contradicting the statement. Option B is incorrect because NF₃ has a smaller dipole moment than NH₃, as the electronegativity of fluorine is counterbalanced by the molecule's symmetry. Lastly, option D is incorrect since SO₃ is a symmetrical molecule with no net dipole moment, making its dipole moment less than that of SO₂, which is polar.