According to the Arrhenius definition, what is the characteristic of an acid?

The Arrhenius definition characterizes an acid as a substance that, when dissolved in water, increases the concentration of hydrogen ions (H⁺) in the solution. According to this definition, an acid is strictly defined by its ability to generate H⁺ ions in an aqueous environment.

When an Arrhenius acid is added to water, it dissociates, releasing H⁺ ions into the solution. This increase in hydrogen ion concentration is what makes the solution acidic, which is an essential characteristic of acids as defined by Arrhenius.

This definition is distinct from the characteristics of bases or other acid definitions, such as the Brønsted-Lowry definition, which involves proton donation. The focus on hydrogen ions aligns specifically with the Arrhenius model, making it the correct choice in this context.