Number of sp Hybridised carbon in the given structure is
`CH_3CH_2CH=C=C=C=CH-C-=CH`

Options

A. 7
B. 5
C. 4
D. 6

Answer

To determine the number of sp hybridized carbon atoms in the given structure `CH3CH2CH=C=C=C=CH-C≡CH`, we can follow these steps:

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

```
H H H H
| | | |
H--C--C--C=C=C=C--C≡C--H
| | |
H H H
```

### Step 2: Identify Carbon Atoms and Their Hybridization
Next, we need to identify the hybridization of each carbon atom in the structure. The hybridization can be determined based on the number of sigma bonds and the presence of lone pairs.

1. **sp Hybridization**: A carbon atom is sp hybridized if it forms two sigma bonds and has two pi bonds (typically found in triple bonds).
2. **sp2 Hybridization**: A carbon atom is sp2 hybridized if it forms three sigma bonds and has one pi bond (typically found in double bonds).
3. **sp3 Hybridization**: A carbon atom is sp3 hybridized if it forms four sigma bonds (single bonds).

### Step 3: Analyze Each Carbon Atom
Now, let's analyze each carbon atom in the structure:

1. **First Carbon (C1)**: CH3 - sp3 hybridized (3 sigma bonds)
2. **Second Carbon (C2)**: CH2 - sp3 hybridized (2 sigma bonds)
3. **Third Carbon (C3)**: CH - sp2 hybridized (1 sigma bond + 1 double bond)
4. **Fourth Carbon (C4)**: C=C - sp hybridized (2 sigma bonds + 2 pi bonds)
5. **Fifth Carbon (C5)**: C=C - sp hybridized (2 sigma bonds + 2 pi bonds)
6. **Sixth Carbon (C6)**: C=C - sp hybridized (2 sigma bonds + 2 pi bonds)
7. **Seventh Carbon (C7)**: C≡C - sp hybridized (1 sigma bond + 3 pi bonds)
8. **Eighth Carbon (C8)**: CH - sp2 hybridized (1 sigma bond + 1 double bond)

### Step 4: Count the sp Hybridized Carbons
From the analysis, we can count the number of sp hybridized carbon atoms:

- C4: sp hybridized
- C5: sp hybridized
- C6: sp hybridized
- C7: sp hybridized

Total sp hybridized carbon atoms = 4

### Conclusion
The number of sp hybridized carbon atoms in the given structure is **4**.