Page 22 - Media Pembelajaran Shofa Niha

s = 4√2,7 10−23/ 27

s =10-6M

[OH-] = 3s = 3 x 10-6M
pOH = - log [OH-]
pOH = log (3 x 10-6]
= 6 – log 3
pH = 14- pOH
= 14 – (6 – log
= 8

b. Jika larutan MgCl2 0,3 M ditetesi larutan NaOH, pada pH berapakah endapan
Mg(OH)2 mulai terbentuk? (Ksp Mg(OH)2 = 3 × 10–11)
Pembahasan :
Ksp Mg(OH)2 = [Mg2+] [OH–]2
3 × 10–11 = 3 × 10–11 [OH–]2
[OH–]2 = 10–10
[OH–] = 10–5M
pOH = 5
pH = 14 – pOH
pH = 14 – 5
= 9
Jadi, pH endapan sebesar 9

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