tentukan campuran larutan yang mmbentuk larutan penyangga 50 mL CH3COOH 0,1 M dengan 50 mL NaOH 0,1 M

CH3COOH + NaOH → CH3COONa + H2O

→ CH3COOH
m = 50 x 0,1 = 5 mmol
r = 5 mmol
s = -

→ NaOH
m = 50 x 0,1 = 5 mmol
r = 5 mmol
s = -

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

M = 5 mmol / (50 + 50)
M = 5 / 100
M = 0,05

→ H2O
m = -
r = 5 mmol
s = 5 mmol

[OH-] = √Kw / Ka . M
[OH-] = √10^-14 / 10^-5 . 5 x 10^-2
[OH-] = √10^-9 . 5 x 10^-2
[OH-] = √10^-11 x 5
[OH-] = √10^-10 x 0,5
[OH-] = √0,5 x 10^-5

pOH = -log [OH-]
pOH = -log √0,5 x 10^-5
pOH = 5 - log√0,5

pH = 14 - (5 - log√0,5)
pH = 14 - 5 + log√0,5
pH = 9 + log√0,5
pH = 9 + (-0,15)
pH = 9 - 0,15
pH = 8,85