Question

Which of the following are present in a dilute aqueous solution of hydrochloric acid?

• A. ${\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{Cl}}^{–}$
• B. ${\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{OH}}^{–}$
• C. ${\mathrm{Cl}}^{–}+{\mathrm{OH}}^{–}$
• D. unionized $\mathrm{HCl}$

Answer 1

The correct option is A

${\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{Cl}}^{–}$

Explanation:

Hydrochloric acid:

• Hydrochloric acid is a strong mineral acid with a chemical formula $\mathrm{HCl}$.
• It is composed of Hydrogen and chlorine atoms.

Dissociation of $\mathrm{HCl}$:

• Hydrochloric acid is a strong acid, thus it dissociates completely into the water to produce hydronium$\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$ and chloride$\left({\mathrm{Cl}}^{-}\right)$ ions.
• The chemical reaction can be depicted as:

$\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Hydronium}\mathrm{ion}}{{\mathrm{H}}_3{\mathrm{O}}^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Chloride}\mathrm{ions}}{{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)}$

Hence, the correct option is A.