Question

How many degrees of unsaturation are there in the following compound?

A.$6$
B.$7$
C.$10$
D.$11$

Answer 1

Hint: Degree of unsaturation is defined as the analysis of structural formula of a compound having unsaturation. Unsaturation means the presence of double bond or triple bond. It is used to calculate the number of rings and pi bonds present in a molecule.

Complete step by step answer:
Unsaturation is defined as the presence of alkene and alkyne in a molecule. Alkene and alkyne consist of pi bonds and are formed by side to side overlapping of the atomic orbitals. A molecule is said to be unsaturated that has double bonds because they have the ability to react with hydrogen in presence of a catalyst. Double bonds consist of one sigma bond and one pi bond. For example, in ethene. In triple bonds, it consists of one sigma bond and two pi bonds.
For the given molecule, the number of degree of unsaturation in this compound can be calculated as follows:
Degree of unsaturation for rings is equal to $1$
Degree of unsaturation for double bonds is equal to $1$
Degree of unsaturation for triple bonds is equal to $2$
Therefore, in this structure,
There are three rings that means, $3$ degree of unsaturation.
There are six double bonds, that means, degree of unsaturation would be $6$
There is only one triple bond, that means, degree of unsaturation would be $2$
Total degree of unsaturation is $3+6+2=11$ .

So, the correct answer is Option D.

Note: In the conclusion, the degree of unsaturation can be calculated as the presence of number of double bonds, number of triple bonds and number of rings in a molecule. Unsaturation is used to calculate the pi bonds in a molecule which is formed by the side to side overlapping of the atomic orbitals.