The most stable conformer cis-cyclohexan-1,4-diol is:

Options

A. (a) Diaxial boat from
B. (b) Diequatiorial boat from
C. (c) Diaxial chair from
D. (d) Diequatiorial chair from

Answer

To determine the most stable conformer of cis-cyclohexan-1,4-diol, we need to analyze the different conformations of the molecule and assess their stability based on steric hindrance and hydrogen bonding.

### Step-by-Step Solution:

1. **Understanding the Structure**:
- Cis-cyclohexan-1,4-diol has two hydroxyl (OH) groups located on the 1st and 4th carbon atoms of the cyclohexane ring. The "cis" designation indicates that both OH groups are on the same side of the ring.

2. **Identifying Conformations**:
- Cyclohexane can adopt several conformations, primarily the chair and boat forms. The chair conformation is generally more stable due to less steric strain compared to the boat form.

3. **Drawing the Chair Conformation**:
- In the chair conformation, we can place the OH groups in either axial or equatorial positions. The equatorial position is preferred for larger substituents to minimize steric hindrance.

4. **Placing OH Groups**:
- For the most stable conformation, place both OH groups in equatorial positions. This minimizes steric hindrance and allows for optimal hydrogen bonding.

5. **Assessing Hydrogen Bonding**:
- In the chair conformation with both OH groups in equatorial positions, the hydroxyl groups can form hydrogen bonds with axial hydrogens on the cyclohexane ring. This intramolecular hydrogen bonding increases the stability of the molecule.

6. **Comparing with Other Forms**:
- If we consider the boat conformation, the OH groups would be on the same axis, leading to increased steric hindrance and less favorable interactions. The chair conformation with axial OH groups would also be less stable due to steric interactions.

7. **Conclusion**:
- The most stable conformer of cis-cyclohexan-1,4-diol is the chair form with both OH groups in equatorial positions, allowing for optimal hydrogen bonding and minimal steric hindrance.

### Final Answer:
The most stable conformer of cis-cyclohexan-1,4-diol is the chair form with both OH groups in equatorial positions.

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