Chapter 19.16, Problem 23P

Interpretation Introduction

Interpretation:

• The strong acid has to be predicted.

Concept Introduction:

Electronic effect:

Electron donating groups decreases acidity by inductive effect (withdrawal of electrons through a sigma bond).  Electron withdrawal increases acidity.  Electron-donating substituents destabilize a base, and decrease the strength of its conjugate acid; electron-withdrawing substituents stabilize a base, which increase the strength of its conjugate base.

Effect of delocalized electrons on ${\text{pK}}_{\text{a}}$Values:

Due to Inductive effect, an anion is stabilized by a nearby electronegative atom.  In the same way, electron delocalization also effective on stabilization of anion.

Rule: The strength of an acid depends on the stability of its conjugate base.