Chapter 19, Problem 65A

a.

Interpretation Introduction

Interpretation : The pH of the solution is to be calculated.

Concept Introduction : The negative logarithm of the concentration of hydrogen ions is the pH of a solution. The formula to calculate pH is given as

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

Answer to Problem 65A

The pH of the solution is $5.62$ .

Explanation of Solution

The concentration of hydrogen ions is $2.4\times {10}^{-6}\text{M}$ .

The formula to calculate pH is given as

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

To calculate the pH of the solution, substitute the values in the above formula:

  $\begin{array}{c}\text{pH=}-{\text{log[H}}^{\text{+}}\text{]}\\ \text{=}-\log \left(2.4\times {10}^{-6}\right)\\ =5.6197\\ \text{pH}=5.62\end{array}$

b.

Interpretation Introduction

Interpretation : The concentration of hydrogen ions is to be calculated.

Concept Introduction : The negative logarithm of the concentration of hydrogen ions is the pH of a solution. The formula to calculate pH is given as

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

Answer to Problem 65A

The concentration of hydrogen ions is $6.3\times {10}^{-14}\text{M}$ .

Explanation of Solution

The pH is $13.20$ .

The formula to calculate pH is given as

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

The hydrogen ion concentration is given by rearranging the above formula.

  ${\text{[H}}^{\text{+}}\text{] = antilog}\left(-\text{pH}\right)$

To calculate the hydrogen ion concentration, substitute the values in the above formula:

  $\begin{array}{c}{\text{[H}}^{\text{+}}\text{] = antilog}\left(-\text{pH}\right)\\ =\text{antilog}\left(-13.20\right)\\ =6.3\times {10}^{-14}\text{M}\end{array}$