Which ion is associated with acidic solutions?

Acidic solutions are characterized by a higher concentration of hydrogen ions in the solution. When an acid dissolves in water, it dissociates to produce hydrogen ions (H⁺). These ions increase the hydronium ion concentration, which is responsible for the acidic properties of the solution, such as a sour taste and the ability to conduct electricity.

In contrast, hydroxide ions are found in basic solutions, while sodium ions and chloride ions do not directly relate to the acidity or basicity of a solution. Sodium ion often comes from salt and does not contribute to the acid characteristic, and chloride ion behaves similarly. Thus, the presence of hydrogen ions is what specifically identifies an acidic solution.