Page 20 - E-MODUL SETS LARUTAN PENYANGGA

Modul Larutan Penyangga Berbasis SETS (science,environment, technology, and society)

Ka = [ ][ +] atau [H ] = Ka x [ ]
+
[ ] [ ]

Contoh soal:
Hitung pH larutan penyangga yang dibuat dari campuran 100 mL larutan CH3COOH
-5
0,1 M dengan 200 mL larutan CH3COONa (Ka CH3COOH= 10 )….
Jawab :

CH3COOH = 100 mL x 0,1 mol/L = 10 mmol (asam lemah)

CH3COONa = 200 mL x 0,1 mol/L = 20 mmol (basa konjugasi)

Maka,

+
[H ] = Ka x [ ℎ]
[ ]
-5
= 10 x [10] = 5 x 10 -6
[20]
+
pH = - log [H ]
-6
= - log 5 x 10
= 6 –log 5

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