What does pH stand for in chemistry?

• A. Potential hydrogen
• B. Positive hydrogen
• C. Power of hydrogen
• D. Primary hydrogen

Answer: (A)

pH is a measure of how acidic or basic a solution is, based on the activity of hydrogen ions. The abbreviation stands for “potential of hydrogen,” a term coined to describe the tendency of hydrogen ions to influence the solution’s acidity. This naming reflects the idea that the acidity depends on the hydrogen ion activity, not just the amount of hydrogen present. The concept is quantified on a log scale: lower pH means more hydrogen ions and a stronger acid, higher pH means fewer hydrogen ions and a more basic (alkaline) solution. The other phrases don’t fit the idea at all—pH isn’t about being positively charged, a power, or a primary hydrogen, but about the hydrogen ion potential in the solution.