Question

How many sigma and pi bonds are in the HCCH molecule?

Answer 1

Hint: The sigma bond is shown as $\sigma -bond$ and pi bond are shown as $\pi -bond$, if all the bonds in the compound are single then there are only sigma bonds, and pi bonds are present in the double and the triple bonds. HCCH molecules are known as ethyne or acetylene.

Complete answer: If the compounds are covalent, it means that there are covalent bonds in them, and there are two types of a covalent bonds, i.e., sigma bond shown as $\sigma -bond$ and pi bond shown as $\pi -bond$.
By counting the number of bonds, we can calculate the number of sigma and pi bonds. Sigma and pi bonds are based on the type of bond present in the molecule, i.e., a single bond, double bond, and triple bond. Therefore, in single bonds, only a sigma bond is present, in the double bond one is sigma and one is pi, and in the triple bond one is a sigma bond and two are pi bonds.
HCCH molecule is known as ethyne or acetylene and it is the first member of the alkyne group, and alkynes are the compounds in which there is a triple bond. The formula of ethyne is given below:
$H-C\equiv C-H$
Since there is one triple bond in this compound, therefore, there are 2 pi bonds present. Rest there are 3 bonds present, so there are 3 sigma bonds.
The diagram is given below:

Therefore, there are 3 sigma bonds and 2 pi bonds present in HCCH.

Note: The sigma bond is a stronger bond than the pi bond because overlapping in the sigma bond is along the internuclear axis but in the pi bond there is sideways overlapping of orbitals.