Chapter 19.2, Problem 13SP

(a)

Interpretation Introduction

Interpretation: The pH of the solution containing $1.0\times {10}^{-12}\text{M}$ hydrogen ion concentration needs to be determined.

Concept Introduction: For a given solution, pH can be calculated as follows:

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

Here, $\left[{\text{H}}^{+}\right]$ is the hydrogen ion concentration.

Explanation of Solution

The given concentration of hydrogen ion is $1.0\times {10}^{-12}\text{M}$ .

The pH of the solution can be calculated as follows:

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

Substitute the values,

  $\begin{array}{c}\text{pH}=-\log \left(1.0\times {10}^{-12}\text{M}\right)\\ =12\end{array}$

Thus, the pH of the solution is 12.

(b)

Interpretation Introduction

Interpretation: The pH of the solution containing $\text{1}\times {\text{10}}^{-4}\text{ M}$ hydrogen ion concentration needs to be determined.

Concept Introduction: For a given solution, pH can be calculated as follows:

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

Here, $\left[{\text{H}}^{+}\right]$ is the hydrogen ion concentration.

Explanation of Solution

The given concentration of hydrogen ion is $\text{1}\times {\text{10}}^{-4}\text{ M}$ .

The pH of the solution can be calculated as follows:

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

Substitute the values,

  $\begin{array}{c}\text{pH}=-\log \left(\text{1}\times {\text{10}}^{-4}\text{ M}\right)\\ =4\end{array}$

Thus, the pH of the solution is 4.