Which of the following compounds is not chiral ?

Options

A. `CH_(3)"CHDCH"_(2)`Cl
B. `CH_(3)CH_(2)`CHDCl
C. `DCH_(2)CH_(2)CH_(2)`Cl
D. `CH_(2)"CHClCH"_(2)` D

Answer

To determine which of the given compounds is not chiral, we need to analyze the structures of each compound and identify the presence of chiral centers. A compound is considered chiral if it has a carbon atom bonded to four different substituents.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to look at the structures of the compounds provided in the question. Let's denote them as Compound 1, Compound 2, Compound 3, and Compound 4.

2. **Analyze Compound 1**:
- Structure: CH3 (methyl group), H (hydrogen), D (deuterium), CH2Cl (chloromethyl group).
- This carbon has four different substituents: CH3, H, D, and CH2Cl.
- **Conclusion**: Compound 1 is chiral.

3. **Analyze Compound 2**:
- Structure: Three hydrogens on one carbon, and on the other carbon, there are two hydrogens, one deuterium, and one chlorine.
- The first carbon has three identical substituents (hydrogens), which means it cannot be a chiral center.
- The second carbon has one hydrogen, one deuterium, and one chlorine, which makes it a chiral center.
- **Conclusion**: Compound 2 has a chiral center but is not entirely chiral due to the first carbon.

4. **Analyze Compound 3**:
- Structure: One carbon has two hydrogens, one deuterium, and one chlorine.
- The other carbon has two hydrogens and one chlorine.
- In this case, both carbons have identical substituents (two hydrogens), meaning there are no chiral centers.
- **Conclusion**: Compound 3 is not chiral.

5. **Analyze Compound 4**:
- Structure: One carbon has three hydrogens, one chlorine, and one carbon chain.
- The other carbon has two hydrogens and one deuterium.
- The first carbon has three identical substituents (hydrogens), which means it cannot be a chiral center.
- However, the second carbon has one hydrogen, one chlorine, and one deuterium, making it a chiral center.
- **Conclusion**: Compound 4 is chiral.

6. **Final Conclusion**: After analyzing all compounds, we find that Compound 3 is the only compound that does not have a chiral center and is therefore not chiral.

### Answer:
The compound that is not chiral is **Compound 3**.