Which of the following heptanols are chiral: 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol.

Options

A. All are chiral
B. 2-heptanol and 3-heptanol
C. 2-heptanol, 3-heptanol & 4-heptanol
D. 3-heptanol and 4-heptanol

Answer

To determine which of the heptanols (1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol) are chiral, we need to analyze the structure of each compound and identify if there are any chiral centers present.

### Step-by-Step Solution:

1. **Understanding Heptanol**:
- Heptanol is an alcohol with a seven-carbon chain (heptane) and an -OH (hydroxyl) group.
- The general formula for heptanol is C7H16O.

2. **Drawing the Structures**:
- **1-Heptanol**: The -OH group is attached to the first carbon.
- Structure: CH3-CH2-CH2-CH2-CH2-CH2-CH2OH
- **2-Heptanol**: The -OH group is attached to the second carbon.
- Structure: CH3-CH(OH)-CH2-CH2-CH2-CH2-CH3
- **3-Heptanol**: The -OH group is attached to the third carbon.
- Structure: CH3-CH2-CH(OH)-CH2-CH2-CH2-CH3
- **4-Heptanol**: The -OH group is attached to the fourth carbon.
- Structure: CH3-CH2-CH2-CH(OH)-CH2-CH2-CH3

3. **Identifying Chiral Centers**:
- A chiral center is a carbon atom that is bonded to four different groups.
- **1-Heptanol**: The first carbon has three hydrogens and one carbon chain, so it is not chiral.
- **2-Heptanol**: The second carbon is attached to a hydroxyl group, a hydrogen, a methyl group (CH3), and a longer carbon chain (pentyl). Thus, it is chiral.
- **3-Heptanol**: The third carbon is attached to a hydroxyl group, a hydrogen, a methyl group, and an ethyl group. Thus, it is also chiral.
- **4-Heptanol**: The fourth carbon is attached to a hydroxyl group, a hydrogen, and two propyl groups (CH2-CH2-CH3). Since two groups are the same (propyl), it is not chiral.

4. **Conclusion**:
- The chiral heptanols are **2-heptanol** and **3-heptanol**.
- Therefore, the answer is that **2-heptanol and 3-heptanol are chiral**.

### Final Answer:
**2-heptanol and 3-heptanol are chiral.**

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