## Chemistry: The Central Science (13th Edition)

For a variation of 2.00 in pH, there is a 100 times variation in $[H^+]$.
$[H^+] = 10^{-pH}$ $[H^+] = 10^{-(pH + 2) } = 10^{-pH} \times 10^{-2}$ $[H^+] = 10^{-(pH - 2) } = 10^{-pH} \times 10^{2}$ If the pH increases by 2, the [H+] gets 100 times smaller, and if the pH decreases by 2, the [H+] gets 100 times greater.