Which scale measures the acidity or basicity of a solution based on hydronium ion concentration?

The pH scale is specifically designed to measure the acidity or basicity of a solution based on the concentration of hydronium ions (H₃O⁺ ions). This scale ranges from 0 to 14, where a pH of 7 is considered neutral (indicating equal concentrations of hydronium ions and hydroxide ions). Values below 7 indicate acidic solutions, which have a higher concentration of hydronium ions, while values above 7 indicate basic (or alkaline) solutions, which have a lower concentration of hydronium ions.

Understanding pH is crucial in many areas of science, including chemistry, biology, and environmental science, as it impacts chemical reactions, biological processes, and the behavior of substances in different environments. The other scales mentioned do not directly relate to the measurement of acidity or basicity in this specific context.