Which solute particles are present in an aqueous solution of HClO?

• A. H_2O molecules and ClO^- ions only
• B. H^+ ions and Cl^- ions
• C. Only HClO molecules
• D. HClO molecules, H^+ ions, and ClO^- ions

Answer: (D)

Verified step by step guidance

1. Recognize that HClO (hypochlorous acid) is a weak acid that partially ionizes in water, meaning it does not completely dissociate into ions.
2. Write the dissociation equation of HClO in water: \(\mathrm{HClO} \rightleftharpoons \mathrm{H^+} + \mathrm{ClO^-}\), showing that it produces hydrogen ions (\(\mathrm{H^+}\)) and hypochlorite ions (\(\mathrm{ClO^-}\)) along with some undissociated HClO molecules.
3. Understand that because the dissociation is partial, the solution contains a mixture of undissociated HClO molecules, \(\mathrm{H^+}\) ions, and \(\mathrm{ClO^-}\) ions.
4. Eliminate options that suggest only ions or only molecules are present, since the equilibrium includes both forms.
5. Conclude that the correct description of the solute particles in the aqueous solution of HClO includes all three species: HClO molecules, \(\mathrm{H^+}\) ions, and \(\mathrm{ClO^-}\) ions.