Which ion is produced by an Arrhenius acid in an aqueous solution?

An Arrhenius acid is defined as a substance that, when dissolved in water, increases the concentration of hydrogen ions (H+) in the solution. However, in aqueous solutions, hydrogen ions do not exist freely; instead, they associate with water molecules to form hydronium ions (H3O+).

When an Arrhenius acid is added to water, it donates protons (H+ ions) to the water molecules, creating H3O+. For example, when hydrochloric acid (HCl) is dissolved in water, it dissociates to produce H+ ions, which then combine with water to give H3O+. Therefore, the production of H3O+ is a direct consequence of the behavior of Arrhenius acids in solution.

This understanding is crucial in various chemical reactions and helps in comprehending the properties of acids and bases, particularly within the context of the Brønsted-Lowry theory, which expands on the definitions provided by Arrhenius.