Hitunglah ph larutan yang terbuat dari 50g NaOH dalam 500 ml larutan

V = 0.5 L
mr naoh = 23 +16+1 = 40
n Naoh = m/mr = 50/40 = 5/4 = 125/100 = 1.25
M = n/v = 1.25/2 = 0.625
OH- = val x M = 1 x 0.625 = 0.625 = 625 x 10^-3
POH = 3 -log 625
PH = 11 + log 625

Larutan
Kimia XI

NaOH adalah basa kuat valensi 1 sesuai jumlah OH 
Mr = Ar Na + Ar O + Ar H
Mr = 23 + 16 + 1
Mr = 40

M = [massa/Mr] x [1000/volum ml]

M = [50/40] x [1000/500]

M = 2,5 mol/liter

[OH⁻] =  valensi x M
[OH⁻] =  1 x 2,5
[OH⁻] = 2,5 mol/lter

pOH = - log [OH⁻]
pOH = - log [25 x 10⁻¹]
pOH = 1 - log 25
pOH = 1 - log [¹⁰⁰/₄]
pOH = 1 - [log 100 - log 4] ingat sifat logaritma
pOH = 1 - [2 - 2.log 2]
pOH = -1 + 2.log 2

pH = 14 - pOH
pH = 14 - (-1 + 2.log 2)

Jadi nilai pH sebesar 13 - 2.log2