Which bond would you rotate around to generate the structure on the right?

Question

Quizplus · Accepted Answer

To generate the structure on the right, we need to rotate the methyl group (CH3) on the left-hand side of the molecule. This group is attached to the carbon that is bonded to the nitrogen (N). Therefore, we need to rotate around the bond between this carbon and nitrogen, which is bond b. Rotating around any of the other bonds (a, c, d) would not result in the same structure as shown on the right.

Which Bond Would You Rotate Around to Generate the Structure