Chapter 6, Problem 91P

(a)

Interpretation Introduction

Interpretation:

Number of alkenes that could be treated with ${\text{H}}_{\text{2}}\text{,}\text{Pd/C}$ in order to prepare methylcyclopentane has to be identified.

(b)

Interpretation Introduction

Interpretation:

The most stable alkene has to be identified.

Concept Introduction:

The stability of the alkene increases as the number of alkyl substituents bonded to $s{p}^2$ carbon increases.  Other hand the most stable alkene has lowest heat of generation.  The reason is they are already having low energy level.  When we hydrogenate an alkene to get alkane, thus alkane is more stable compared to alkene, therefore energy is released.  Hence it is more stable and more stable alkene.

(c)

Interpretation Introduction

Interpretation:

The compound has smallest heat of hydrogenation has to be found.

Concept Introduction:

The stability of the alkene increases as the number of alkyl substituents bonded to $s{p}^2$ carbon increases.  Other hand the most stable alkene has lowest heat of generation.  The reason is they are already having low energy level.  When we hydrogenate an alkene to get alkane, thus alkane is more stable compared to alkene, therefore energy is released.  Hence it is more stable and more stable alkene.