Chapter 16, Problem 72AP

Interpretation Introduction

Interpretation:

Why the pH of $1.00\times {10}^{-7}\text{ M}$ HCl is not exactly 7.00 should be explained.

Concept Introduction:

The concentration of hydrogen ions in a solution determines the acidity of a solution. If concentration of hydrogen ion is more than the solution is more acetic, if it is low, solution is less acidic.

The pH of solution is defined as negative log of hydrogen ion concentration thus, it can be calculated as follows:

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

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

Similarly, pOH of a solution is defined as negative log of hydroxide ion concentration thus, it can be calculated as follows:

$\text{p}\text{O}\text{H}=-\text{log}\left[{\text{OH}}^{-}\right]$

Here, $\left[{\text{OH}}^{-}\right]$ is concentration of hydroxide ion.

pH and pOH of a solution are related to each other as follows:

$\text{p}\text{H}+\text{p}\text{O}\text{H}=14$.