Chapter 8.11, Problem 18P

a)

Interpretation Introduction

Interpretation: The relative ${\text{pK}}_{\text{a}}$ values of cyclopentadiene and cycloheptatriene have to be estimated.

Concept Introduction:

Criteria for Aromaticity:

1. 1. A molecule must be cyclic.
2. 2. Every atom in the ring must have a p-orbital.
3. 3. The molecule must be planar.
4. 4. $\text{π-}$ Cloud must contain an odd number of pairs of $\text{π-electrons}\text{.}$

b)

Interpretation Introduction

Interpretation: The relative ${\text{pK}}_{\text{a}}$ values of cyclopropene and cyclopropane have to be estimated.

Concept Introduction:

Criteria for Aromaticity:

1. 5. A molecule must be cyclic.
2. 6. Every atom in the ring must have a p-orbital.
3. 7. The molecule must be planar.
4. 8. $\text{π-}$ Cloud must contain an odd number of pairs of $\text{π-electrons}\text{.}$