Larutan 25ml CH3COOH 0,2 M(Ka=1 x 10-5) dicampurkan dengan 25 ml larutan NaOH 0,1 M maka harga PH larutan

→ CH3COOH
m = 5 mmol
r = 2,5 mmol
s = 2,5 mmol

→ NaOH
m = 2,5 mmol
r = 2,5 mmol
s = 0

→ CH3COONa
m = -
r = 2,5 mmol
s = 2,5 mmol

→ H2O
m = -
r = 2,5 mmol
s = 2,5 mmol

[H+] = Ka . 2,5mmol / 2,5mmol
[H+] = 10^-5 . 1
[H+] = 10^-5

pH = -log [H+]
pH = -log 10^-5
pH = 5 - log1
pH = 5