Q. 6.81 - An Introduction to General, Organic, and Biological Chemistry

Question

Identify each of the following molecules as polar or nonpolar:
a. ${\mathrm{CS}}_2$
b. ${\mathrm{NF}}_3$
c. ${\mathrm{CHF}}_3$
d. ${\mathrm{SO}}_3$

Step-by-Step Solution

Answer

Part(a) ${\mathrm{CS}}_2$is nonpolar.

Part(b) ${\mathrm{NF}}_3$ is polar.

Part(c) ${\mathrm{CHF}}_3$ is polar.

Part(d) ${\mathrm{SO}}_3$ is nonpolar.

Part(a) Step 1 : Given information

We have to identify that ${\mathrm{CS}}_2$ molecule is polar or nonpolar.

Part(a) Step 2 : Simplify

The ${\mathrm{CS}}_2$ molecule is a nonpolar molecule.
Because of the molecule's linear nature.The $\mathrm{C}-\mathrm{S}$ bond has a small dipole moment.

Part(b) Step 1 : Given information

We have to identify that ${\mathrm{NF}}_3$molecule is polar or nonpolar.

Part(b) Step 2 : Simplify

${\mathrm{NF}}_3$ is polar molecule.
The $\mathrm{N}$ is somewhat positive and the $\mathrm{F}$ is partially negative in polar $\mathrm{N}-\mathrm{F}$ bonds.
The molecule is slightly assymetric with regard to the negative centres around the $\mathrm{N}$ atom due to the lone pair of electrons on the $\mathrm{N}$ atom (VSEPR theory)
The $\mathrm{N}-\mathrm{F}$ bonds' dipole moments do not cancel out, resulting in a dipole moment that makes the molecule polar.

Part(c) Step 1 : Given information

We have to identify that ${\mathrm{CHF}}_3$ molecule is polar or nonpolar.

Part(c) Step 2 : Simplify

The chemical trifluoromethane, often known as fluoroform ${\mathrm{CHF}}_3$, is classed as a polar molecule.
The bond angles between carbon, fluorine, and hydrogen in trifluoromethane (which has tetrahedral molecular geometry) are $109.5$degrees.

Part(d) Step 1 : Given information

We have to identify that ${\mathrm{SO}}_3$ molecule is polar or nonpolar.

Part(d) Step 2 : Simplify

Sulfur trioxide ${\mathrm{SO}}_3$ is a nonpolar molecule with three $\mathrm{S}-\mathrm{O}$ bonds and no lone pair of electrons in the central sulphur atom.
Because of its trigonal planar symmetrical structure, ${\mathrm{SO}}_3$ is also a nonpolar molecule.