Chapter 22, Problem 37R

To determine

To Describe: The result of dissolving $\text{HCl}$ in water to form hydrochloric acid.

Explanation of Solution

Introduction: The tendency of a substance to produce hydrogen ions when dissolved in water classifies the substance as an acid.

  $\text{HCl}$ dissolves in water to give ${\text{H}}^{+}$ and ${\text{Cl}}^{-}$ ions. The ${\text{H}}^{+}$ ions gets attracted to the negative ends of the water molecules to form hydronium ( ${\text{H}}_3{\text{O}}^{+}$ ) ions.

The chemical equation for the reaction:

  ${\text{HCl+H}}_2\text{O}\to {\text{H}}_3{\text{O}}^{+}{\text{+Cl}}^{-}$

The presence of more ${\text{H}}_3{\text{O}}^{+}$ ions than hydroxide ions makes the solution acidic.

Conclusion: $\text{HCl}$ dissociates in water to give ${\text{H}}_3{\text{O}}^{+}$ ions and ${\text{Cl}}^{-}$ ions. It is the ${\text{H}}_3{\text{O}}^{+}$ ions,which makes the solution acidic.