Chapter 7, Problem 115E

Interpretation Introduction

Interpretation: The pH of 0.10 M ${\text{CoCl}}_{\text{3}}$ solution needs to be determined.

Concept Introduction: The ionization of an acid is represented as follows:

  $\text{HA}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)\rightleftharpoons {\text{H}}_{\text{3}}^{}{\text{O}}^{+}\left(aq\right){\text{+A}}^{-}\left(aq\right)$

The acid ionization constant is represented as $K_a$ .

The expression will be as follows:

  $K_a=\frac{\left[{\text{H}}_{\text{3}}^{}{\text{O}}^{+}\right]\left[{\text{A}}^{-}\right]}{\left[\text{HA}\right]}$ ............ (1)

The pH of the solution can be calculated as follows:

  $\text{pH}=-\log \left[{\text{H}}_{\text{3}}{\text{O}}^{+}\right]$

Here, $\left[{\text{H}}_{\text{3}}{\text{O}}^{+}\right]$ is hydronium ion concentration.