Question

The ratio of \[\sigma \] and \[\pi \] bond in benzene is:
A. 4:1
B. 6:1
C. 4:3
D. 8:1

Answer 1

Hint: Sigma bond is represented by the single bond and present in the saturated hydrocarbon whereas pi bond is represented by the double and triple and present in unsaturated hydrocarbon.

Complete Step-by-Step Answer:
- In the given question, we have to find the ratio of the sigma and pi bond found in the benzene.
- As we know that sigma bond is the single covalent bond formed by the head on the overlapping of the s and p orbital or s - s orbital.
- Whereas pi bond is the double or triple bond which is formed by the side to side overlapping of the two p orbitals.
- Now to calculate the ratio of sigma and pi bond, firstly we have to draw the structure of the benzene i.e.

- As we can see that there are three double bonds present in the benzene ring so from Each double bond one pi bond is formed.
- So, a total of 3 pi bonds are present in the benzene ring.
- Now, as we can see that there are 6 \[\sigma \] bonds present between a carbon-carbon atom and 6 \[\sigma \] bonds between carbon-hydrogen atoms so a total of 12 \[\sigma \] bonds is present in the benzene ring.
- Hence, the ratio of sigma and pi bond will be:
\[\frac{\sigma }{\pi }\text{ = }\frac{12}{3}\text{ = }\frac{4}{1}\text{ or 4:1}\]

Therefore, option A is the correct answer.

Note: The sigma bond has the electron density directly between the bonded atoms. Sigma bond is symmetric whereas pi bond is asymmetric. The pi bond has no electric density directly between the bonded atom.