pH of the aqueous solution = 9
Therefore, [H+] = [tex]10^{-9}[/tex] = 0.000000001 M
pH + pOH = 14
Therefore, pOH = 14 - pH = 14 - 9 = 5
[OH-] = [tex]10^{-5}[/tex] = 0.00001 M
Concentration of OH- ions is more than H+ ions by
[tex]\frac{0.00001}{0.000000001} = 10,000[/tex] times
Thus, an aqueous solution at pH 9 has free OH-ions 10,000 times more than free H+ ions.