How does the pH scale measure acidity and basicity?

The pH scale is a logarithmic scale used to quantify the acidity or basicity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, indicating a balanced concentration of hydrogen ions (H⁺) and hydroxide ions (OH⁻). Values below 7 indicate an increase in hydrogen ion concentration, which corresponds to increasing acidity. Conversely, values above 7 reflect a decrease in hydrogen ions and an increase in hydroxide ions, indicating basicity.

Understanding this scale is important in chemistry because it helps categorize substances and predict their behavior in reactions. For example, a solution with a pH of 1 is very acidic, while a solution with a pH of 13 is very basic. The choice of a scale from 0 to 14 is specifically tied to the behavior of water and the dissociation of water molecules into ions, making the range meaningful for empirical studies and practical applications in both chemistry and biology.