Which of the following molecules is(are) polar ?
I. NF₃ (trigonal pyramidal)
II. BF₃ (trigonal planar)
III. IF₃ (T-shape)

Question

Which of the following molecules is(are) polar ? I. NF₃ (trigonal pyramidal) II. BF₃ (trigonal planar) III. IF₃ (T-shape)

Quizplus · Accepted Answer

A molecule is polar if it has a net dipole moment. For a molecule to have a net dipole moment, the electronegativity difference between the atoms should be significant and there should be an asymmetric distribution of the electrons in the molecule. Among the given options, I and III have an asymmetric distribution of electrons, and their bond dipoles do not cancel out. Therefore, they are polar. Option II has a symmetric distribution of electrons and its bond dipoles cancel out, so it is non-polar. Thus, the best choice is E, which includes the two polar molecules, I and III.

Which of the Following Molecules Is(are) Polar