Here's why:

* The pH scale is logarithmic: This means each whole number change in pH represents a tenfold change in acidity.

* Lower pH means higher acidity: A pH of 1.2 is 10 times more acidic than a pH of 2, and 100 times more acidic than a pH of 3.

Think of it this way: The lower the pH, the more hydrogen ions (H+) are present in the solution, making it more acidic.