Question

What is the bond polarity of $N{H_3}$?
A) $N{H_3}$ is a non-polar molecule
B) $N{H_3}$ is a polar molecular
C) $N - H$ bond is polar
D) Both B and C

Answer 1

We also have to know that the polarity comes when Hydrogen atoms are attached to an electronegative species. A molecule is said to be polar when the distribution of electrons between the atoms that are covalently bonded to it is not polar. On the other hand A nonpolar molecule is the one in which electrons are distributed equally.

Complete answer:
We will going to see the structure, hybridization and geometry before answering this question
We can draw the structure of ammonia as,

We also remember that the hybridization of ammonia is $s{p^3}$
Molecular Geometry: Pyramidal
As we know that every $N - H$ bond is polar in ammonia since the electronegativities of both Nitrogen and Hydrogen are different. The molecular geometry of ammonia is not symmetrical due to which it will not have 0 dipole moment and polarities will not be cancelled.
$N$ will have partial negative charge while H atom will have partial positive charge. $N$ is much more electronegative than the H atom, due to which ammonia turns out to be a polar molecule.
There are $3N - H$ bonds in ammonia and one lone pair of atoms on $N$.
The distance between $N - H$ bond is $101.7pm$ and the angle between $HNH$ is $107.8^\circ$
Example of Polar molecule: $N{H_3}$, ${H_2}O$
Example of Non Polar molecule: $C{H_3},NaCl$
Option A) this is an incorrect option as ammonia is not non polar as discussed above.
Option B) this option is right as Ammonia is a polar molecule which we have discussed but we have other options too, so look at all the options
Option C) this option is right as $N - H$ bond is polar due to the variant electronegativity between H and N, but we will look at other options too.
Option D) this is a correct option as it contains both the options which are right.

Note:
We have to remember that the bond polarity basically tells about the polarity of bond. Since ammonia is a polar molecule it will have polar bonds as well, which is $N - H$ bond in this case.