Question

The number of sigma and pi bonds in benzene are:
a. 6 sigma and 3 pi bonds
b. 12 sigma and 3 pi bonds
c. 9 sigma and 3 pi bonds
d. 6 sigma and 6 pi bonds

Answer 1

Benzene is a hydrocarbon composed of six carbons connected via covalent bond, and exists in the form of a ring. It has three alternating double bonds which makes the compound very stable.

Complete step by step answer:
Benzene is an aromatic compound of carbon and hydrogen. The molecular formula for benzene is ${{C}_{6}}{{H}_{6}}$.
Let us draw the structure of Benzene.

To calculate the number of sigma bonds in this, we can draw the skeletal structure by only drawing the sigma bonds –

As we can see, there are 6 C-H bonds, 6 C-C bonds.
Therefore, we can say that there are a total of 12 sigma bonds in benzene.
Now, looking at the structure of benzene, we can see that there are 3 C=C bonds.
Therefore, there are 12 sigma bonds and 3 pi bonds. Benzene is therefore made up of 15 covalent bonds.

Therefore, the answer is – option (b) – The number of sigma and pi bonds in benzene are 12 and 3, respectively.

Additional Information:One single bond contains one sigma bond; a double bond contains one sigma and one pi bond.Similarly, a triple bond contains one sigma and two pi bonds.

Note: Benzene exists as a colorless and highly flammable liquid with a sweet smell. This sweet smell is produced as a result of aromaticity of the compound. Aromaticity of benzene arises due to the continuous cyclic pi bonds between the carbon atoms. It is a very stable compound. Benzene is naturally present in crude oil and is also an elementary petrochemical.