Page 22 - E-LKS Hidrolisis Garam
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Contoh Soal
1. Tentukan pH dari larutan garam CH3COONa 0,1 M (Ka CH3COO = 10 )
-5
Jawab :
-
+
CH3COONa (aq) → CH3COO (aq) + Na (aq)
0,1 0,1 0,1
-
-
[OH ] = √ [ ] pOH = − log [OH ]
10 −14 −1 -5
=√ 10 −5 10 = - log10
= √10 −10 = 5
= 10 -5 pH = 14-5 = 9
Jadi pH larutan garam CH3COONa 0,1 M adalah 9
2. Tentukan pH larutan 100 mL HCl 0,2 M yang direaksikan dengan 100 NH3
-5
0,2 M (Kb NH3 = 10 )
Jawab :
n HCl = M x V n NH3 = M x V
= 0,2 x 100 = 0,2 x 100
= 20 mmol = 20 mmol
HCl(aq) + NH3(aq) → NH4Cl(aq)
m 20 mmol 20 mmol -
r 20 mmol 20 mmol 20 mmol
s - - 20 mmol
+
+
[H ] = √ [ ] pH = − log [H ]
-5
−1
=√ 10 −14 10 = - log10
10 −5
= √10 −10 = 5
= 10 -5
21 E-LKS Berorientasi Chemoentrepreneurship
