Which one of the following does not have `sp^(2)` hybridised carbon ?

Options

A. Acetone
B. Acetic acid
C. Acetonitrile
D. Acetamide

Answer

To determine which of the given compounds does not have an `sp²` hybridized carbon atom, we need to analyze the hybridization of the carbon atoms in each compound. Here’s a step-by-step breakdown of the analysis:

### Step 1: Understand `sp²` Hybridization
`sp²` hybridization occurs when a carbon atom is bonded to three other atoms, which can include double bonds. In `sp²` hybridization, one `s` orbital and two `p` orbitals mix to form three equivalent `sp²` hybrid orbitals, resulting in a trigonal planar geometry.

### Step 2: Analyze Each Compound
1. **Acetone (CH₃COCH₃)**:
- Structure: CH₃-C(=O)-CH₃
- The carbon in the carbonyl group (C=O) is `sp²` hybridized because it is bonded to three atoms (two CH₃ groups and one O).
- **Conclusion**: Contains `sp²` hybridized carbon.

2. **Acetic Acid (CH₃COOH)**:
- Structure: CH₃-C(=O)-OH
- Similar to acetone, the carbon in the carbonyl group (C=O) is also `sp²` hybridized.
- **Conclusion**: Contains `sp²` hybridized carbon.

3. **Acetonitrile (CH₃CN)**:
- Structure: CH₃-C≡N
- The carbon in the nitrile group (C≡N) is `sp` hybridized because it is involved in a triple bond with nitrogen (C≡N) and has only one single bond to the CH₃ group.
- **Conclusion**: Does not contain `sp²` hybridized carbon.

4. **Acid Amide (CH₃C(=O)NH₂)**:
- Structure: CH₃-C(=O)-NH₂
- The carbon in the carbonyl group (C=O) is `sp²` hybridized.
- **Conclusion**: Contains `sp²` hybridized carbon.

### Final Answer
Based on the analysis, **Acetonitrile (CH₃CN)** is the compound that does not have an `sp²` hybridized carbon atom.