Chapter U4, Problem C16.4RE

Interpretation Introduction

(a)

Interpretation:

The concentration of hydrogen ions in lemon juice should be predicted.

Concept introduction:

The full form of pH is the potential of pH. In other words, it explains the strength of the hydrogen ion in the solution. It is given by the formula,

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

Answer to Problem C16.4RE

The concentration of hydrogen ions in lemon juice is 0.01 M.

Explanation of Solution

The pH of the lemon juice is given as 2. The concentration of hydrogen ions in lemon juice is calculated as follows:

$\begin{array}{c}\text{pH}=-\log \left[{\text{H}}^{+}\right]\\ \text{2}=-\log \left[{\text{H}}^{+}\right]\\ \log \left[{\text{H}}^{+}\right]=-2\\ \left[{\text{H}}^{+}\right]={10}^{-2}\\ \left[{\text{H}}^{+}\right]=0.01\text{M}\end{array}$

Therefore, the concentration of hydrogen ions in lemon juice is 0.01 M.

Interpretation Introduction

(b)

Interpretation:

The concentration of hydroxide ions in lemon juice should be predicted.

Concept introduction:

The full form of pH is the potential of pH. In other words, it explains the strength of the hydrogen ion in the solution. It is given by the formula,

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

Now, the concentration of hydroxide ions can be calculated using hydrogen ion as follows:

$\left[{\text{OH}}^{-}\right]=\frac{{10}^{-14}}{\left[{\text{H}}^{+}\right]}$

Answer to Problem C16.4RE

The concentration of hydroxide ions in lemon juice is ${10}^{-12}\text{M}$.

Explanation of Solution

The pH of the lemon juice is given as 2. The concentration of hydrogen ions in lemon juice is 0.01 M.

The concentration of hydroxide ions in lemon juice is calculated as follows:

$\begin{array}{c}\left[{\text{H}}^{+}\right]\left[{\text{OH}}^{-}\right]={10}^{-14}\\ {10}^{-2}\left[{\text{OH}}^{-}\right]={10}^{-14}\\ \left[{\text{OH}}^{-}\right]=\frac{{10}^{-14}}{{10}^{-2}}\\ \left[{\text{OH}}^{-}\right]={10}^{-12}\text{M}\end{array}$

Therefore, the concentration of hydroxide ions in lemon juice is ${10}^{-12}\text{M}$.