Konsentrasi ion OH– dalam larutan NaOH sebesar 5.10–¹² M . Kosentrasi ion H+ yaitu

NaOH ==> Na+ + OH-

[OH-] = [ NaOH ] 
[OH-] = 5 x 10^-12

[H+] = 10^-14/[OH-] 
[H+] = 10^-14/5 x 10^-12
[H+] = 2 x 10^-3

Semoga dapat membantu !!