How many `sigma " and "pi` bonds are present in `HC-=C-CH=CH-CH_(3)` ?

Options

A. `9sigma,4pi`
B. `10sigma,3pi`
C. `6sigma,6pi`
D. `5sigma,5pi`

Explanation

To determine the number of sigma (σ) and pi (π) bonds in the compound \( HC \equiv C - CH = CH - CH_3 \), we can follow these steps:

### Step 1: Write the Structural Formula
The compound can be represented structurally as follows:
- The first carbon (C) is bonded to a hydrogen (H) and has a triple bond with the second carbon (C).
- The second carbon (C) is then bonded to the third carbon (C) with a single bond.
- The third carbon (C) is bonded to the fourth carbon (C) with a double bond.
- The fourth carbon (C) is bonded to three hydrogens (H).

### Step 2: Identify the Types of Bonds
1. **Sigma Bonds (σ)**: These are the first bonds formed between any two atoms. Each single bond and the first bond of a double or triple bond is a sigma bond.
2. **Pi Bonds (π)**: These are the additional bonds formed in double or triple bonds. Each double bond has one pi bond, and each triple bond has two pi bonds.

### Step 3: Count the Sigma Bonds
- **Between H and C (first carbon)**: 1 σ bond (H-C)
- **Between C and C (first and second carbon)**: 1 σ bond (C≡C)
- **Between C and C (second and third carbon)**: 1 σ bond (C-C)
- **Between C and C (third and fourth carbon)**: 1 σ bond (C=C)
- **Between C and H (fourth carbon)**: 3 σ bonds (C-H)

Now, let's sum them up:
- H-C: 1 σ
- C≡C: 1 σ
- C-C: 1 σ
- C=C: 1 σ
- C-H (three bonds): 3 σ

Total σ bonds = 1 + 1 + 1 + 1 + 3 = **7 σ bonds**

### Step 4: Count the Pi Bonds
- **C≡C**: 2 π bonds (from the triple bond)
- **C=C**: 1 π bond (from the double bond)

Total π bonds = 2 + 1 = **3 π bonds**

### Final Count
- Total σ bonds = 7
- Total π bonds = 3

### Conclusion
The compound \( HC \equiv C - CH = CH - CH_3 \) has **7 sigma bonds and 3 pi bonds**.

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