The pH scale ranges from 0 to 14. The pH value indicates the acidity or alkalinity (basicity) of a solution. A pH of 7 is considered neutral, indicating a balanced concentration of hydrogen ions (H+) and hydroxide ions (OH-) in the solution. Values below 7 indicate acidity, with lower values indicating stronger acidity. Values above 7 indicate alkalinity (basicity), with higher values indicating stronger alkalinity.