Question

The total number of $\sigma$ and $\pi$ bonds present in azobenzene are:
A.24 $\sigma$ , 6 $\pi$
B.25 $\sigma$, 7 $\pi$
C.28 $\sigma$, 6 $\pi$
D.27 $\sigma$, 6 $\pi$

Answer 1

To obtain the solution of this question, we must first understand the concept of $\sigma$ bonds and $\pi$ bonds. Then we must draw the molecular structure of azobenzene and then individually count $\sigma$ bonds and $\pi$ bonds.

Complete step by step answer:
Before proceeding with the solution of this question, let us understand some basic concepts and terms:
$\sigma$ and $\pi$ bonds are both covalent in nature
$\sigma$ bonds are formed when there is end to end overlapping of orbitals. It can also be represented as a single bond
$\pi$ bonds are formed when there is overlapping of a lobe of one atomic orbital. It can also be represented as a double bond.
The bond strength of $\sigma$ bonds is stronger than $\pi$ bonds
The structure of Azobenzene can be given by:

From this structure, we can observe that the number of single and double bonds are:
Number of single bonds = 25 = number of $\sigma$ bonds
Number of double bonds = 7 = number of $\pi$ bonds
Hence, there are 25 $\sigma$ bonds and 7 $\pi$ bonds

Hence, Option B is the correct option.

Note:
Azobenzene is a molecule whose structure comprises two phenyl rings linked by a N=N double bond; the parent compound of the azobenzene class of compounds. One of the largest applications of the compound azobenzene takes place in the colouring and dye industry.