Page 33 - modul kleas XI larutan penyangga
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3. Jawaban : D
Pembahasan :
NH3 + NH4Cl = 3 : 6
-
[OH ] =
3
= 1,8 x 10 -5
6
-5
-6
= 0,3 x 10 = 3 x 10
= 6 – log 3
pOH = 6 – log 3
pH = 14 – (6 – log 3)
= 8 + log 3
4. Jawaban : B
Pembahasan :
HCOOH + NaOH → HCOONa + H2O
m : 0,15 mol 0,10 mol
b : 0,10 mol 0,10 mol` 0,1 mol
s : 0,05 mol - 0,1 mol
+
[H ] =
HCOOH
+
[H ] =
HCOONa
0,05
= 2 x 10 -5
0,10 mol
-5
= 10 M
+
pH = - log [H ]
-5
= - log 10 = 5
5. Jawaban : B
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