Chapter 16, Problem 26A

Interpretation Introduction

Interpretation:

The reason expressing the acidity of a solution in terms of its pH is to be explained.

Concept Introduction:

The acidity or alkalinity of a solution is expressed by determining P^H of the solution. P^H of a solution is defined as negative logarithm of the concentration of H+ ion in the solution. P^H is expressed as-

  ${\mathrm{P}}^H=-log[H^{+}]$

Answer to Problem 26A

Because the concentration of H+ ion in an aqueous solution is usually very small

  ${\mathrm{P}}^H=-log[H^{+}]$

Explanation of Solution

Because the concentration of H+ ion in an aqueous solution is usually so small that it is difficult to compare the acidity of various solutionin terms of the molarity of hydrogen ion. To make the number easier to deal with, the acidity of the solution is expressed in term of the pH scale.

P^H of a solution is defined mathematically as negative logarithm of the concentration of H+ ion in the solution. P^H is expressed as-

  ${\mathrm{P}}^H=-log[H^{+}]$