Chapter 13, Problem 37QAP

Interpretation Introduction

(a)

Interpretation:

The decreasing order of the acid strength should be determined.

Concept introduction:

The weak acid does not dissociate completely in a chemical reaction thus, the ionization equation is in equilibrium.

For a general reaction of ionization of weak acid as follows:

$\text{HA}\rightleftharpoons {\text{H}}^{+}+{\text{A}}^{-}$

The expression for dissociation constant of the reaction is as follows:

${\text{K}}_a\text{=}\frac{\left[{\text{H}}^{+}\right]\left[{\text{A}}^{-}\right]}{\left[\text{HA}\right]}$

The $p{K}_a$ of a weak acid is defined as negative log of $K_a$ or,

$pK=-\log K_a$

Interpretation Introduction

(b)

Interpretation:

The acid with the largest $K_a$ value should be determined.

Concept introduction:

The weak acid does not dissociate completely in a chemical reaction thus, the ionization equation is in equilibrium.

For a general reaction of ionization of weak acid as follows:

$\text{HA}\rightleftharpoons {\text{H}}^{+}+{\text{A}}^{-}$

The expression for dissociation constant of the reaction is as follows:

${\text{K}}_a\text{=}\frac{\left[{\text{H}}^{+}\right]\left[{\text{A}}^{-}\right]}{\left[\text{HA}\right]}$

The $p{K}_a$ of a weak acid is defined as negative log of $K_a$ or,

$pK=-\log K_a$