Chapter 14.9, Problem 16P

Interpretation Introduction

Interpretation: The given compounds are to be ranked in increasing order of stability.

Concept introduction: Diene is a hydrocarbon that contains two $\text{C}=\text{C}$ double bonds in a compound.

Conjugated diene consists of two double bonds that are separated by a single bond, whereas isolated diene also consists of two double bond but they are separated by two more carbon atoms.

The stability of diene depends upon the number of conjugated double bond. Conjugation involves overlapping of $p$ orbitals with three or more adjacent atoms. Due to overlapping of $p$ orbitals, the electron density of sigma bonds increases. Thus, the energy of the molecule decreases and the molecule become more stable. Conjugated diene is more stable than isolated diene.