Question

Which compound in the following pair would you expect to have the greater dipole moment μ? Why? Select the single best answer. NaF or HF Hydrogen fluoride has the larger dipole moment because sodium has a greater atomic radius than hydrogen. Sodium fluoride has the larger dipole moment because hydrogen has a greater atomic radius than sodium. Hydrogen fluoride has the larger dipole moment, because sodium is more electronegative than hydrogen. Sodium fluoride has the larger dipole moment, because hydrogen is more electronegative than sodium.

Answer 1

Sodium fluoride has the larger dipole moment, because hydrogen is more electronegative than sodium.

Option D.

8.156

1.86

Explanation:

Dipole moment of a molecule is defined as the product of the distance between two atoms of a molecule and their partial charges. This value of dipole moment of a molecule gives the idea of how polar a molecule will be. The molecules with lower dipole moment are apolar, and the molecules with higher dipole moment are polar.

The dipole moment becomes higher in those molecules where one of the participating atoms are highly electropositive and the other one is highly electronegative. This leads to the electropositive atom donating the electron pull towards the electronegative atom, thereby increasing the partial charge difference.

In case of HF and NaF, the sodium atom is more electropositive than hydrogen atom. This leads to more difference in partial charges between the corresponding atoms, hence more dipole moment.