What is the range of numbers used on the pH scale?

• A. 0 to 14
• B. 1 to 14
• C. 0 to 7
• D. 7 to 14

Answer: (A)

pH is a measure of how acidic or basic a solution is, based on the hydrogen ion concentration. In water at typical room temperature, the pH scale is defined from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, while values above 7 indicate basicity. The extremes reflect very strong acids (near 0) and very strong bases (near 14). So the range used on the pH scale is 0 to 14. (Note: in non-aqueous solutions or at different temperatures, the usable range can shift, but 0–14 is the standard for aqueous solutions at room temperature.)