Draw 1,2,3,4,5,6-hexamethylcyclohexane with all the methyl groups
b. in equatorial positions.

Verified step by step guidance

1. Start by drawing the basic structure of cyclohexane in its chair conformation. This is the most stable conformation of cyclohexane, where alternating carbon atoms are positioned above and below the plane of the ring.
2. Label the six carbon atoms in the cyclohexane ring (C1 through C6) to keep track of the positions where the substituents (methyl groups) will be added.
3. Recall that in the chair conformation, each carbon atom has two substituent positions: one axial (pointing straight up or down) and one equatorial (pointing outward and slightly angled). For this problem, all methyl groups need to be placed in equatorial positions.
4. Add a methyl group (-CH₃) to each carbon atom (C1 through C6) in the equatorial position. Ensure that the equatorial positions alternate directions around the ring to maintain the correct geometry of the chair conformation.
5. Double-check your drawing to confirm that all six methyl groups are in equatorial positions and that the chair conformation is correctly represented. This ensures the structure is accurate and adheres to the problem's requirements.

Key Concepts

Cyclohexane Conformation

Cyclohexane can adopt different conformations, primarily chair and boat forms. The chair conformation is the most stable due to minimized steric strain and torsional strain. Understanding these conformations is crucial for visualizing how substituents, like methyl groups, are positioned on the ring.

Equatorial vs. Axial Positions

In the chair conformation of cyclohexane, substituents can occupy either equatorial or axial positions. Equatorial positions extend outward from the ring, reducing steric hindrance, while axial positions point up or down, potentially causing 1,3-diaxial interactions. For stability, bulky groups prefer equatorial positions.

Substituent Effects on Stability

The placement of substituents on cyclohexane affects the overall stability of the molecule. In the case of 1,2,3,4,5,6-hexamethylcyclohexane, having all six methyl groups in equatorial positions minimizes steric interactions, leading to a more stable structure compared to having any in axial positions.