To determine which option does not have a chiral center, we need to identify the presence of a carbon atom that is bonded to four different groups. A chiral center is typically a carbon atom that has four distinct substituents.
### Step-by-Step Solution:
1. **Understand the Definition of Chiral Center**:
- A chiral center is an atom (usually carbon) that is bonded to four different groups. If any two groups are the same, it is not a chiral center.
2. **Analyze Each Option**:
- **Option 1**: CH2, D, CH2, Cl
- The carbon atom has two hydrogen atoms attached, which means it is not bonded to four different groups. Thus, this carbon does not have a chiral center.
- **Option 2**: CH3, CHd, CH2, Cl
- The carbon in this structure has one hydrogen, one CH3, one CH2Cl, and one deuterium (D). All four groups are different, indicating that this carbon is a chiral center.
- **Option 3**: CH3, CH, Cl, CH2D
- This carbon has one hydrogen, one chlorine, one CH3, and one CH2D. Again, all four groups are different, confirming that this is a chiral center.
- **Option 4**: CH3, CHOH, CH2, CH3
- In this carbon, we have one hydrogen, one hydroxyl group (OH), one CH3, and one CH2. All groups are different, indicating that this is also a chiral center.
3. **Conclusion**:
- After analyzing all the options, we find that the only option without a chiral center is **Option 1**.
### Final Answer:
The chiral center is absent in **Option 1**.
