Which of the following is not a chiral ?

Options

A. 3-Methylhexane
B. 2, 3-Dihydroxypropanoic acid
C. 2, 3-Dibromobutane
D. Butan-2-ol

Answer

To determine which of the given compounds is not chiral, we need to analyze the structure of each compound and identify the presence of chiral centers. A chiral center is typically an sp³ hybridized carbon atom that is bonded to four different substituents. If a compound has a chiral center, it is considered chiral. Conversely, if it has a plane of symmetry or does not have any chiral centers, it is considered achiral (not chiral).

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Let's assume we have four compounds to analyze:
1. Compound A
2. Compound B
3. Compound C (2,3-Dibromobutane)
4. Compound D (Butane-2-ol)

2. **Analyze Compound A**:
- Check if it has a chiral center. If it has one sp³ hybridized carbon with four different groups, it is chiral. If not, it is achiral.

3. **Analyze Compound B**:
- Similar to Compound A, check for the presence of a chiral center. If it has two or more identical groups on the carbon, it is not chiral.

4. **Analyze Compound C (2,3-Dibromobutane)**:
- This compound has two chiral centers (C-2 and C-3). Each of these carbons is bonded to four different groups, thus making the compound chiral. However, if both bromine atoms are on the same side (cis), there can be a plane of symmetry, making it potentially achiral.

5. **Analyze Compound D (Butane-2-ol)**:
- This compound has one chiral center at the second carbon (C-2) which is bonded to a hydroxyl group, a methyl group, an ethyl group, and a hydrogen atom. Therefore, it is chiral.

6. **Conclusion**:
- Based on the analysis, if Compound C has symmetry (both bromines on the same side), it is not chiral. The other compounds have chiral centers and are chiral.

### Final Answer:
- The compound that is not chiral is **Compound C (2,3-Dibromobutane)** if it has symmetry.