Question

What are the total number of $\sigma $ and $\pi $ bonds in naphthalene ${{C}_{10}}{{H}_{8}}$?

Answer 1

Hint: If a compound has carbon atoms, then there are two types of bonds: sigma and pi bond. The single bond represents the single bond and the double and triple bond represents the pi bond. Two electrons are involved in the formation of a bond.

Complete answer:
In an organic compound, there are mostly carbon atoms present. So, the bonds are mostly made up of two bonds: a sigma ($\sigma $) bond and a pi($\pi $) bond. The compound is having only a sigma bond, if the compound has a single bond. If the compound has one sigma bond and one pi bond, then the compound is having a double bond. If the compound has one sigma bond and two pi bonds, then the compound is having a triple bond. The sigma electrons are the electrons that form the sigma bond and pi electrons are the electrons that form the pi bond.
So the compound given in the question is naphthalene whose formula is ${{C}_{10}}{{H}_{8}}$. The structure of the naphthalene is given below:

So in the structure, there are a total of 24 bonds in which 5 are the double bonds and the rest 19 bonds are the single bond. The open structure is given below:

Therefore, there are 19 sigma ($\sigma $) bonds and 5 pi ($\pi $) bonds and there are 38 sigma-electrons and 10 pi-electrons in the system.

Note:
If the compounds have two sigma electrons and four pi electrons then the compound has a triple bond. These bonds are only formed if the compound has a covalent bond or we can say that both the sigma and pi bonds are covalent.