HELP! Calculate the pH of the following solutions: a) [OH-] = 3.1x10^-8 M
pH = 7.51
pH = 3.18
pH = 8.00
pH = 6.49
pH = 3.10

b) [H3O+] = 5.2x10^-7 M
pH = 7.72
pH = 7.00
pH = 6.28
pH = 5.27
pH = 5.20

c) [OH-] = 5.9x10^-5 M
pH = 5.00
pH = 5.90
pH = 4.23
pH = 5.59
pH = 9.77

d) [OH-] = 5.9x10^-3 M