If the PH of a Solution is Decreased from 9

Question

If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H⁺ has decreased to one-tenth (1/10) what it was at pH 9.
B) concentration of H⁺ has increased tenfold (10X) compared to what it was at pH 9.
C) concentration of OH⁻ has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH⁻ has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H⁺ has increased tenfold (10X) and the concentration of OH⁻ has decreased to one-tenth (1/10) what they were at pH 9.

Accepted Answer

The pH scale is logarithmic, meaning a decrease in pH by 1 unit results in a tenfold increase in the concentration of H⁺ ions. Conversely, as the concentration of H⁺ increases, the concentration of OH⁻ decreases, making option E correct.