Jika 0,2 gram NaOH dilarutkan dalam air hingga volumenya 400 ml. Berapakah pH larutan NaOH tersebut

NaOH → Na^+ OH^-

[NaOH] = mol NaOH / volume(liter)
= gr NaOH/Mr NaOH / 0,4
= 0,2/40 / 4/10
= 0,0125 M = [OH^-]


pOH = -log[1,25.10^-2]
pOH = 2-log1,25
pH + pOH = 14
pH = 14-(2-log1,25)
pH = 12+log1,25