Question

which of the following have non-zero dipole moments?
(A) $S{F_4}$
(B) $S{F_6}$
(C) $Xe{O_2}{F_2}$
(D) $S{O_3}$

Answer 1

Hint : Dipole moment is the measure of polarity of a chemical bond within a molecule. It occurs whenever there is a separation of positive and negative charges. So, polarity is nothing but a separation of electric charge leading to a molecule having an electric dipole moment.

Complete Step By Step Answer:
The dipole moment is represented by $\mu$ (mue).
Dipole moment is given by
$\mu = \delta d$
Where $\delta$ -charge ( ${\delta ^ + }$ and ${\delta ^ - }$ )
d-distance between partial charges.
The unit of $\mu$ is debye(D).
$S{F_4}$ molecule – name of the molecule is sulphur tetrafluoride. The hybridization type of the molecule is $s{p^3}d$ hybridization. The molecular geometry is trigonal bipyramidal. It contains four bond pairs and one lone pair.
It has a see-saw shape.
(all diagrams are drawn using paint 3d)

The molecular geometry of the $S{F_4}$ molecule is not linear or any geometrical shape that will cancel out the partial negative charges on the fluorine, so the overall molecule is polar which makes it have a dipole moment of around 0.632D. So it has a non-zero dipole moment.
$S{F_6}$ molecule – name of the molecule is sulphur hexafluoride. The molecule have $s{p^3}{d^2}$ hybridization. The molecular geometry is octahedral.

The $S{F_6}$ molecule has no dipole moment because each $S - F$ bond dipole is balanced by one of equal magnitude pointing in opposite direction of the other side of the molecule. So the net charge of the molecule is zero.
$Xe{O_2}{F_2}$ molecule – the molecule name is xenon dioxide difluoride. The molecule have $s{p^3}d$ hybridization. The molecular geometry is trigonal bipyramidal.

The molecule is polar. It has 4 bond pairs and 1 lone pair. Since this molecule has a lone pair, it is not symmetrical and therefore, has a net polar moment.
$S{O_3}$ molecule – name of the molecule is sulphur trioxide. The molecule have $s{p^2}$ hybridization. The molecular geometry is trigonal planar.

$S{O_3}$ is a planar molecule with three bond angles 120 degrees apart. The individual dipole moments of $S - O$ bond cancel out each other due to which the dipole moment of the molecule is zero.
Hence the option (A) and (C) have non zero dipole moments.

Note :
from dipole moment
-Ionic characters can be calculated.
-Geometry of the molecule can be predicted.
-Nature of the molecule can be predicted.
Keep in point that the dipole moment is a vector quantity.