When aqueous solutions of potassium fluoride and hydrochloric acid are mixed, an aqueous solution of potassium chloride and hydrofluoric acid results. Write the net ionic equation for the reaction. (Use the solubility rules provided in the OWL Preparation Page to determine the solubility of compounds.)

F⁻ (aq) + H⁺ (aq) ⇄ HF (aq)

Explanation:

When aqueous solutions of potassium fluoride and hydrochloric acid are mixed, an aqueous solution of potassium chloride and hydrofluoric acid results. The corresponding molecular equation is:

KF (aq) + HCl (aq) ⇄ KCl (aq) + HF (aq)

The full ionic equation includes all the ions and the molecular species. HF is a weak acid so it exists mainly in the molecular form.

K⁺ (aq) + F⁻ (aq) + H⁺ (aq) + Cl⁻ (aq) ⇄ K⁺ (aq) + Cl⁻ (aq) + HF (aq)

The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the molecular species.

F⁻ (aq) + H⁺ (aq) ⇄ HF (aq)