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`

Answer

To determine the number of sigma (σ) and pi (π) bonds in the compound HC≡C-CH=CH-CH₃, we can follow these steps:

### Step 1: Draw the Structure
First, we need to visualize the structure of the compound. The given compound can be expanded as follows:

```
H H
\ /
C
||
C
/ \
H C
/ \
H H
```

### Step 2: Identify the Bonds
Now, we will identify the types of bonds present in the structure:

1. **Single Bonds (σ bonds)**: Every single bond between atoms is a sigma bond.
2. **Double Bonds**: A double bond consists of one sigma bond and one pi bond.
3. **Triple Bonds**: A triple bond consists of one sigma bond and two pi bonds.

### Step 3: Count the Sigma Bonds
- **Between H and C**: Each H atom bonded to C is a single bond (σ).
- **Between C and C**: The first bond in a double bond is a σ bond, and the first bond in a triple bond is also a σ bond.

Let's count:
- From HC (1 σ bond)
- From C≡C (1 σ bond)
- From C=CH (1 σ bond)
- From CH-CH₃ (1 σ bond)
- Each C atom has 2 H atoms, contributing to additional σ bonds.

Counting all:
- H-C (1)
- C-C (1 for the triple bond)
- C-C (1 for the double bond)
- C-H (3 from CH₃ and CH)
- Total σ bonds = 10

### Step 4: Count the Pi Bonds
- For the double bond (C=CH), there is 1 π bond.
- For the triple bond (C≡C), there are 2 π bonds.

Counting all:
- C=CH (1 π bond)
- C≡C (2 π bonds)
- Total π bonds = 3

### Final Count
- Total σ bonds = 10
- Total π bonds = 3

### Conclusion
The number of sigma bonds is 10, and the number of pi bonds is 3.