Chapter 24, Problem 1DE

Practice Exercise 1
A solution at 25° C has pOH = 10.53. Which of the following statements is or are true?

1. The solution is acidic.
2. The pH of the solution is 14.00 − 10.53.
3. For this solution [OH^-] = 10-10.53 M.
1. Only one of the statements is true.
2. Statements (i) and (ii) are true.
3. Statements (ii) and (iii) are true.
4. Statements (ii) and (iii) are true.
5. All three statements are true.

Interpretation Introduction

Interpretation:

The statements those are true for the given solution among the given statements.

Concept introduction:
The pH is defined as the negative logarithm of concentration of ${\text{H}}^{\text{+}}$ ions. The pOH is defined as the negative logarithm of concentration of ${\text{OH}}^{-}$ ions.
The pH and pOH of solution is related to each other. The formula relating these two quantities is,

$\text{14}=\text{pH}+\text{pOH}$

Answer to Problem 1DE

Solution:

All the three statements are true. Hence, option (e) is correct.

Explanation of Solution

The pOH of the solution is 10.53.

The pH of the solution is calculated by the formula,

$\text{pH}=14-\text{pOH}$

Substitute the value of pOH in the above equation.

$\begin{array}{c}\text{pH}=14-\text{10}\text{.53}\\ =\text{3}\text{.47}\end{array}$

As the pH of the solution is less than 7. The solution is acidic.

The concentration of ${\text{OH}}^{-}$ ions in the solution is calculated by the formula,

$\begin{array}{c}\text{pOH}=-\log \left[{\text{OH}}^{-}\right]\\ \left[{\text{OH}}^{-}\right]={\text{10}}^{\left(-\text{pOH}\right)}\end{array}$

Where,

• $\left[{\text{OH}}^{-}\right]$ is the concentration of ${\text{OH}}^{-}$ ions in the solution.

Substitute the value of pOH in the above equation.

$\left[{\text{OH}}^{-}\right]={\text{10}}^{\left(-10.53\right)}$

Thus, all the three statements are true for the given solution.

Conclusion

All the three statements are true. Hence, option (e) is correct.