Underlined carbon is sp hybridised in-

Options

A. `CH_(3)CH=CH_(2)`
B. `CH_(3)CH_(2)-NH_(2)`
C. `CH_(3)CONH_(2)`
D. `CH_(3)CH_(2)CN`

Answer

To determine which carbon is sp hybridized in the given compounds, we need to analyze the hybridization of each carbon atom based on its bonding.

### Step-by-Step Solution:

1. **Understanding Hybridization**:
- Carbon can be sp3, sp2, or sp hybridized depending on the number of sigma and pi bonds it forms:
- **sp3**: 4 sigma bonds (single bonds)
- **sp2**: 1 double bond (1 sigma + 1 pi) and 2 single bonds (2 sigma)
- **sp**: 1 triple bond (1 sigma + 2 pi) and 1 single bond (1 sigma)

2. **Analyzing the First Compound (CH3)**:
- The carbon in CH3 forms four single bonds (to three hydrogens and one carbon).
- Therefore, it is **sp3 hybridized**.

3. **Analyzing the Second Compound**:
- If the second compound is something like C2H6 (ethane), each carbon forms four single bonds.
- Thus, both carbons are **sp3 hybridized**.

4. **Analyzing the Third Compound (CH3CONH2NH2)**:
- The carbon in the carbonyl group (C=O) forms one double bond with oxygen and two single bonds (to CH3 and NH2).
- Hence, this carbon is **sp2 hybridized**.

5. **Analyzing the Fourth Compound (Cyanide, CN)**:
- The carbon in cyanide (C≡N) forms a triple bond with nitrogen.
- Therefore, this carbon is **sp hybridized**.

6. **Conclusion**:
- The carbon that is sp hybridized is the one in the cyanide compound.

### Final Answer:
The underlined carbon is sp hybridized in the cyanide compound.