Sorry you're wrong! pH and pOH values are not the same and when added together they must equal 14. Let'g go over how to solve this:
pOH=14-pH => 14-7.31=6.69
[H+]=10-pH => 10-7.31=4.90e-8
[OH-]=10-pOH => 10-6.69=2.04e-7
The correct Answer is B.
pOH=14-pH => 14-7.31=6.69
[H+]=10-pH => 10-7.31=4.90e-8
[OH-]=10-pOH => 10-6.69=2.04e-7
The correct Answer is B.