What defines the concentration of an alkaline solution?

The concentration of an alkaline solution is defined by a high concentration of hydroxide ions. In chemical terms, an alkaline solution, or a basic solution, exhibits a pH greater than 7, which indicates that hydroxide ions (OH⁻) are present in greater amounts compared to hydrogen ions (H⁺).

When discussing the properties of alkaline solutions, it is important to understand that they result from the dissociation of certain bases in water, releasing hydroxide ions into the solution. This increased number of hydroxide ions is what gives alkaline solutions their characteristic of being slippery, neutralizing acids, and often conducting electricity.

Therefore, an alkaline solution's defining feature is indeed the high concentration of hydroxide ions, making it distinctly different from neutral solutions or acidic solutions where hydrogen ions would be more prevalent or balanced against hydroxide ions.