Question

What is the number of pi bonds in the molecule below?

Answer 1

4.

Explanation:

Most of the carbon-carbon bonds in this molecule (which appears to be a 1,5-hexadiyne) are single and contain only sigma bonds. Each of the carbon-carbon triple bonds involves three pi bonds. There are two triple carbon-carbon bonds in the molecule and therefore we have four pi bonds in the molecule.

(Since the photo was a little bit shaky, here's another condensed structure formula for your reference)

http://www.chemspider.com/Chemical-Structure.62610.html

Answer 2

There are 4 pi bonds in the molecule shown.

Explanation:

Pi bonds are present in double or triple bonds.

A single bond contains `1sigma` bond and `0 pi` bond.
A double bond contains `1sigma` and `1pi` bond.
A triple bond contains `1sigma` and `2pi` bonds.

There are 2 triple bonds in the molecule, therefore, `2xx2=4pi` bonds.

This post may also help you!

Check out this video on how to count sigma and pi bonds!