Chapter 15, Problem 119QRT

(a)

Interpretation Introduction

Interpretation:

The percentage ionization of acetic acid has to be calculated, when the concentration of acetic acid is$\text{0}\text{.100}\text{M}$ and ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ is$\text{0}\text{.00134}\text{mol/L}$.

Concept Introduction:

Percent ionization:

A quantitative measure of the degree of ionization is percent ionization.

For a weak, monoprotic acid $\text{HA}$percent ionization can be calculated as follows,

  $\text{percent}\text{ionization}=\frac{{\text{[H}}_{\text{3}}{\text{O}}^{\text{+}}\text{]}}{\text{[HA]}}\times 100\%$

(b)

Interpretation Introduction

Interpretation:

The percentage ionization of acetic acid has to be calculated, when the concentration of acetic acid is $\text{0}\text{.100}\text{M}$ and acetate ion is$\text{0}\text{.050}\text{M}$.

Concept Introduction:

Acid ionization constant, $K_a$:

The ionization of a weak acid $\text{HA}$can be given as follows,

${\text{HA}}_{(aq)}\rightleftarrows {\text{H}}^{+}{}_{(aq)}+{\text{A}}^{\text{-}}{}_{(aq)}$

The equilibrium expression for the above reaction is given below.

  ${\text{K}}_{\text{a}}\text{=}\frac{{\text{[H}}^{\text{+}}{\text{][A}}^{\text{-}}\text{]}}{\text{[HA]}}$

Where

  ${\mathrm{K}}_a$ is acid ionization constant,

  $[{\text{H}}^{\text{+}}\text{]}$  is concentration of hydrogen ion

  $[{\text{A}}^{\text{-}}\text{]}$  is concentration of acid anion

  $[\text{HA]}$ is concentration of the acid