Question

What is the ph of a solution with a hydroxyl ion (oh-) concentration of 10-10 m?

Answer 1

PH is the potential of hydrogen, pH provides a measure of the concentration of hydrogen ion while pOH scale provides the concentration of OH- ions.
pH denotes the negative logarithm of concentration of hydrogen while pOH denotes the negative logarithm of the concentration OH- ions.
Therefore; in this case the pOH= -log (OH-)
                                                  = - log (10^-10)
                                                  =  10
If the pOH is 10 then the pH of the solution will be 4