A 100. mL solution of NaOH has a pH of 13.51. If you add 110 mL of water to the original solution, what will the resulting pH be?

13.19

Explanation:

pH + pOH = 14

pOH = 14 – pH

        = 14 – 13.51

        = 0.49

When water is added to the solution, then the concentration of the solution is changed.

Initial volume is 100 mL

Final volume = 100 + 10 = 110 mL

0.323 M ×100 mL = M2 × 110

[OH] = 0.154 M

pOH = -log 0.154  

        = 0.81

pH = 14 – 0.81

     = 13.19

pH of the resulting solution is 13.19 .