Question

The dihedral (torsional) angle (in degrees) between the two methyl groups in the most stable conformation of n-butane is .......
(Round off to nearest integer)

Hint:

In the most stable conformation of butane (the anti conformation), the dihedral angle between the two methyl groups is 180°.

Answer 1

Correct Answer: 180

Step 1: Understanding the most stable conformation of n-butane.
In the most stable conformation of n-butane, the two methyl groups are positioned in the anti conformation, where the dihedral angle between them is maximized to reduce steric hindrance.

Step 2: Analyzing the torsional angle.
In the anti conformation, the dihedral angle between the two methyl groups is 180°.

Step 3: Conclusion.
The dihedral angle is \( \boxed{180^\circ} \).