Final answer:
pH measures the concentration of hydrogen ions (H+) in a solution, reflecting its acidity or alkalinity. Values below 7 on the pH scale are acidic, while values above 7 are alkaline.
Step-by-step explanation:
What does pH measure? The pH measures the concentration of hydrogen ions (H+) in a solution. This is a reflection of the solution's acidity or alkalinity. A pH of 7 is considered neutral, indicating neither acidic nor alkaline properties. On the pH scale, a value below 7 signifies an acidic solution with a higher concentration of hydrogen ions, while a value above 7 signifies a more alkaline solution with a lower concentration of hydrogen ions. Each step on the pH scale represents a tenfold change in ion concentration. For instance, a pH of 4 has 10 times more hydrogen ions than a pH of 5.