A solution of pH 5 is diluted 100 times. Find the pH of the resulting solution.

First, we calculate of the concentration of the H + ions in the solution from the pH given. Then, calculate the new concentration after dilution. Calculation are as follows:

pH = - log[H+]

5 = - log[H+]

[H+] = 1 x 10^-5 M

M1V1 = M2V2

1 x 10^-5 M (V1) = M2 (100V1)

M2 = 1 x 10^-7

pH = - log[ 1 x 10^-7 ]

pH = 7