Chapter 7, Problem 17DQ

Interpretation Introduction

Interpretation: Thepossibility of negative value of pH for a solution and the reason of lower pH value for strong acid solution than weak acid solution needs to be explained.

Concept Introduction: An acid is the substance that gives H+ or ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ ions in its aqueous solution.

  ${\text{HA}}_{\text{(aq)}}{\text{ + H}}_{\text{2}}{\text{O}}_{\text{(l) }}\stackrel{}{\to }{\text{H}}_{\text{3}}{\text{O}}^{\text{+}}{}_{\text{(aq)}}{\text{+A}}^{\text{-}}{}_{\text{(aq)}}$

On the contrary, a base gives OH- ions in its aqueous solution.

  ${\text{BOH}}_{\text{(aq)}}\rightleftharpoons {\text{B}}^{\text{+}}{}_{\text{(aq)}}{\text{+ OH}}^{\text{-}}{}_{\text{(aq)}}$

The pH scale is the range from 0 to 14, whereas 0 to 7 value indicates the acidic medium and 7 to 14 stands for basic solution.