Final answer:
The pH scale is a range of values that describes the acidity or basicity of a solution based on the concentration of hydrogen ions. A lower pH indicates more acidity, while a higher pH indicates more alkalinity.
Step-by-step explanation:
The pH scale is the range of values from 0 to 14 that describes the acidity or basicity of a solution. The pH is defined as the negative logarithm of the hydronium ion (H3O+) concentration in a solution. In other words, it represents the concentration of hydrogen ions in a solution. A lower pH value indicates a higher concentration of hydrogen ions, making the solution more acidic, while a higher pH value indicates a lower concentration of hydrogen ions, making the solution more basic or alkaline.