Question

An example of non-polar molecule is:
(A) $B{{F}_{3}}$
(B) $Cl{{F}_{3}}$
(C) $PC{{l}_{3}}$
(D) $S{{O}_{2}}$

Answer 1

Hint: Polarity describes the distribution of an electrical charge around the molecule. The distribution of charge plays an important role in their classification. Knowing the distribution of charges across the given molecules can lead us to solve the given problem.

Complete answer:
Let us understand what we mean by polarity and its classification;
The two-broad classification of molecules with respect to their polarities are polar molecules and nonpolar molecules.
1. Polar molecules- In these molecules, charge is unevenly distributed across the bonds. It has a dipole moment as a part of the molecule has partial positive charge and the other has partial negative charge.
The polar molecule has asymmetrical shape, lone pair of electrons or central atom bounded to those atoms which have different electronegativities. They are hydrophilic and soluble in polar solvents.
2. Non-polar molecules- In these molecules, charge is evenly distributed across the bonds. These are formed when the electrons are equally shared between the atoms in that molecule.
The symmetrical arrangement of electrons cancels out the dipole moment. They are insoluble in water but are soluble in nonpolar compounds.
Now, let us move towards the illustration given;
$B{{F}_{3}}$ molecules have $s{{p}_{2}}$ hybridisation and hence have trigonal planar geometry. It has symmetrical geometry and hence, it cancels out the dipole moment. Hence, $B{{F}_{3}}$ is a nonpolar molecule.
Whereas, other molecules i.e. $Cl{{F}_{3}}$, $PC{{l}_{3}}$, $S{{O}_{2}}$ are asymmetrical in geometry. So, there is an uneven distribution of charges and thus, they are polar.

Therefore, option (A) is correct.

Note: Do note that ionic compounds such as NaCl are also polar. And, non-polar molecules can also form with polar bonds arranged in a pattern where electric charges will cancel out each other.