What defines the concentration of a neutral solution?

The concentration of a neutral solution is characterized by having an equal amount of hydrogen ions (H⁺) and hydroxide ions (OH⁻). In a neutral solution, such as pure water at 25°C, the concentrations of these ions are equal, which means that the solution is neither acidic nor basic. This balance is crucial because it determines the pH level of the solution, which is 7 for neutral solutions.

In this context, when the concentrations of H⁺ and OH⁻ are equal, the solution exhibits neutrality, devoid of any excess acidity or alkalinity. This principle is essential in understanding acid-base chemistry and the behavior of various substances in aqueous solutions.

Other options, while focusing on concentrations of specific ions, do not characterize a neutral solution. High concentrations of hydrogen ions would indicate acidity, while high concentrations of hydroxide ions would indicate alkalinity. A low concentration of all ions doesn't directly define neutrality either, as it may simply indicate a dilute solution rather than a balanced one.