Question

Given below are two statements regarding conformations of n-butane. Choose the correct option. 

• A. Both Statement I and Statement II are false
• B. Statement I is false but Statement II is true
• C. Statement I is true but Statement II is false
• D. Both Statement I and Statement II are true

Hint:

Anti-staggered conformations are always the most stable in alkanes.

Answer 1

The Correct Option is D

To determine the correctness of the statements regarding the conformations of n-butane, we need to review their stability.

1. Understanding Conformations of n-Butane:
   • n-Butane has several conformations due to the rotation around the C-C bond.
   • The major conformations are: fully eclipsed, gauche, and anti.
2. Analyzing the Conformations:
   • Fully Eclipsed Conformation (X): This occurs when the two methyl groups (CH₃) are directly aligned with each other. It is the least stable due to maximum steric hindrance.
   • Anti Conformation (Y): The methyl groups are positioned 180 degrees apart, minimizing repulsive interactions. It is the most stable conformation.
3. Conclusion:
   • Statement I: "Fully eclipsed conformation is the least stable" is true.
   • Statement II: "Anti conformation is the most stable" is true.

Therefore, the correct answer is: Both Statement I and Statement II are true.