sebanyak 200 mL larutan Ch3COOH 1 M dicampur dengan 800 mL larutan NaOH 0,25 M. jika Ka Ch3COOH = 1,0 x 10-5 maka pH larutan

Mol CH3COOH = 200/1000 × 1 = 2 × 10-¹ mol
mol NaOH = 800/1000 × 25×10-² = 2 × 10-¹ mol

CH3COOH+NaOh=>CH3COONa+H2O
M : (2×10-¹) (2×10-¹) –
R : (2×10-¹) (2×10-¹) (2×10-¹)
S : – – (2×10-¹)

[CH3COONa] = (2×10-¹)/1 = 2×10-¹ M

[H+] = √(Kw/Ka × [garam])
[H+] = √(10-¹⁴/10-5 × (2×10-¹))
[H+] = √(10^(-10) × 2) = √2 × 10^(-5)

pH = – log [H+]
pH = – log (√2 × 10^(-5))
pH = 5 – log √2