Chapter U4.20, Problem 1E

Interpretation Introduction

Interpretation:

The change in the pH of a solution when water is added to it needs to be explained.

Concept introduction:

The relation between pH and hydrogen ion concentration is as follows:

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

Answer to Problem 1E

The pH increases when water is added to an acidic solution.

Explanation of Solution

When water is added to an acidic solution, the concentration of acid decreases and so [H⁺] also decreases. As pH is related with H+ as negative logarithm, so pH will increase.

For example, if an acidic solution is diluted to 1000 times, then [H⁺] is reduced by 1000 times and the pH will increase.