JEE Chemistry 2023 Question with Solution

Step-by-step solution

Standard Method

Given: Four conformations are shown.

Find: The most stable conformation.

From the solution, stability depends on Vanderwaal and torsional strain.

In the chair conformation of cyclohexane, bulky groups prefer the equatorial position to minimize steric hindrance and achieve greater stability.

In conformation (1), both methyl (Me) groups are in equatorial positions, resulting in the lowest steric hindrance and highest stability.

Therefore, the correct option is A.

Common mistakes

• Placing emphasis only on drawing appearance and ignoring steric effects is incorrect. Stability must be judged by minimizing van der Waals and torsional strain. Instead, compare how the Me groups are positioned.

• Assuming any conformation with methyl groups far apart is automatically most stable is incomplete. The key point is whether bulky groups occupy equatorial positions. Instead, identify the conformation where both methyl groups are equatorial.