Chapter 19, Problem 2STP

Interpretation Introduction

Interpretation : The hydrogen ion concentration of orange juice is to be compared with the hydrogen ion concentration of tomato juice.

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 2STP

Correct answer: Option (B)

Compared to the hydrogen ion concentration of orange juice, the hydrogen ion concentration of tomato juice is 10 times lower.

Explanation of Solution

Reason for correct option:

The pH of orange juice is $3.5$ .

The pH of tomato juice is $4.5$ .

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 of orange juice, substitute the values in the above formula:

  $\begin{array}{c}{\text{[H}}^{\text{+}}\text{] = antilog}\left(-\text{pH}\right)\\ =\text{antilog}\left(-3.5\right)\\ =3.16\times {10}^{-4}\text{M}\end{array}$

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

  $\begin{array}{c}{\text{[H}}^{\text{+}}\text{] = antilog}\left(-\text{pH}\right)\\ =\text{antilog}\left(-4.5\right)\\ =3.16\times {10}^{-5}\text{M}\end{array}$

The hydrogen ion concentration of tomato juice is 10 times lower than the orange juice.

So, the correct answer is option B.

Conclusion

Reasons for incorrect options:

Options (A), (C), (D): All these options are irrelevant. The calculation of hydrogen ion concentration does not give these options.