ANSWER
Step-by-step explanation
Given that;
pH is 5
Follow the steps below
Firstly, we need to find the H^+ of the sample
Recall, that pH is 5
Therefore, [H^+] = 1 x 10^-5 M
Find pOH?
pH + pOH = 14
pH = 5
5 + pOH = 14
subtract 5 from both sides of the equation
5 - 5 + pOH = 14 - 5
pOH = 9
Find OH^- using the below formula