If a solution has a pH greater than 7, what type of solution is it?

A solution with a pH greater than 7 is classified as basic, also known as alkaline. The pH scale ranges from 0 to 14, where 7 represents a neutral solution, such as pure water. Values lower than 7 indicate acidity, with stronger acids having lower pH values. Conversely, as the pH increases beyond 7, the concentration of hydroxide ions (OH⁻) increases, which contributes to the basicity of the solution.

In basic solutions, substances like sodium hydroxide or potassium hydroxide can be present, providing the hydroxide ions that elevate the pH. Pure water at 25°C has a pH of exactly 7, which is neutral; therefore, any pH above 7 indicates a solution that has become more basic, meaning there are more hydroxide ions than hydrogen ions relative to water.

Understanding this concept is critical, especially in applications involving acid-base chemistry, where the pH can influence reactions, stability of compounds, and overall behavior of the solution.