Question

What is the total number of sigma bonds found in the following compound?
\[ \text{CH}_3\text{CH} = \text{C} = \text{CH} - \text{C} \equiv \text{C} - \text{H} \]

• A. 10
• B. 11
• C. 12
• D. 9
• E. 13

Hint:

To count sigma bonds, remember that every single bond, one bond in a double bond, and one bond in a triple bond is a sigma bond. Double bonds contribute 1 sigma bond, and triple bonds contribute 1 sigma bond.

Answer 1

The Correct Option is B

To determine the number of sigma bonds, we need to count the sigma bonds in each bond in the given structure: 
The given compound is: \[ {CH}_3{CH} = {C} = {CH} - {C} \equiv {C} - {H} \] 1. Sigma bonds in single bonds:
- Each C-H bond is a single bond, and there are 4 C-H bonds (1 from each methyl group and 1 from the terminal CH group) contributing 4 sigma bonds.
- Each C-C bond in the structure is a single bond (sigma bond), and there are 3 C-C bonds, contributing 3 sigma bonds.
2. Sigma bonds in double bonds:
- Each double bond consists of 1 sigma bond and 1 pi bond. There are 2 double bonds in the compound (C=C), contributing 2 sigma bonds.
3. Sigma bonds in triple bonds:
- Each triple bond consists of 1 sigma bond and 2 pi bonds. There is 1 triple bond (C≡C) contributing 1 sigma bond.
Now, adding all the sigma bonds together:
- 4 sigma bonds from C-H bonds,
- 3 sigma bonds from C-C single bonds,
- 2 sigma bonds from C=C double bonds,
- 1 sigma bond from C≡C triple bond.
Thus, the total number of sigma bonds is: \[ 4 + 3 + 2 + 1 = 11 \] Thus, the correct answer is option (B), 11.