Chapter 17, Problem 17.48P

Interpretation Introduction

Interpretation: The most acidic and least acidic labeled $\text{H}$ atoms are to be identified by considering A and B compounds, and an explanation for the choices is to be stated.

Concept introduction: The strength of acid depends upon the stability of conjugate base formed by the abstraction of proton by base. A planar, cyclic, completely conjugated compound that has $4n+2\pi$ electrons is aromatic. A planar, cyclic, completely conjugated compound that has $4n\pi$ electrons is antiaromatic. The aromatic conjugate base is more stable than the nonaromatic and an antiaromatic conjugate base (least stable).