JEE Chemistry 2025 Question with Solution

Given: We need the sum of sigma ($\sigma$) and pi ($\pi$) bonds in Hex-1,3-dien-5-yne.

Find: Total number of bonds present as the sum of sigma and pi bonds.

The solution gives the structure as

Each double bond has $1$ sigma bond and $1$ pi bond, while each triple bond has $1$ sigma bond and $2$ pi bonds.

Counting all bonds in the given structure gives a total of $17$ bonds.

Therefore, the sum of sigma and pi bonds is $17$.

Given: Count sigma and pi bonds separately for the given compound.

Find: The total $\sigma + \pi$ bond count.

Use the bond-type rule:

• Single bond $\rightarrow$ only $1\sigma$
• Double bond $\rightarrow$ $1\sigma + 1\pi$
• Triple bond $\rightarrow$ $1\sigma + 2\pi$

The provided solution identifies the final total directly from the displayed structure and states that the total number of sigma and pi bonds is $17$.

Therefore, the required numerical value is $17$.