Chapter 3, Problem 3.49P

Interpretation Introduction

Interpretation:

It is to be determined if all the atoms in $\text{buta-1, 3-diene}$ have to reside in the same plane or not.

Concept introduction:

Groups which are connected by a single bond have the ability to rotate freely relative to each other. But the groups which are connected by a double bond do not rotate freely. In case of a double bond, the pi bond would be broken because during rotation, the overlap between p orbitals would be destroyed. When two atoms are connected by a double bond, those two atoms and all the atoms directly attached to them, prefer to lie in the same plane.