Question

If [H+] = 5.0 x 10^-8, calculate:
pH
pOH
[OH-]

Answer 1

Answer: pH=7.30 (2 sig figs means going 2 places past the decimal point since we are using logs.)

pOH=6.70

[OH-]=2.0x10^-7 M

Explanation: To get pH, you have to take the -log of the concentration of hydronium ions. To find pOH, subract pH from 14. To get [OH-] we need to do 10^-pOH to go in reverse essentially. Hope this helps.