Soal nomor 3 sampai 5...???

Kelarutan & Hasilkali Kelarutan
Kimia XI

[3]
(a) Mg(OH)₂ (s) ⇄ Mg²⁺ (aq) + 2 OH⁻ (aq)
(b) Ag₂S (s) ⇄ 2 Ag⁺ (aq) + S²⁻ (aq)
(c) BaCrO₄ (s) ⇄ Ba²⁺ (aq) + CrO₄²⁻ (aq)

[4]
pH = 10 ⇒ pOH = 4
[OH⁻] = 10⁻⁴

Mg(OH)₂ adalah basa bervalensi 2

[OH⁻] = M x valensi
10⁻⁴ = M x 2
M = 5 x 10⁻⁵ ⇒ kelarutan (biasa disimbolkan "s")

Mg(OH)₂ (s) ⇄ Mg²⁺ (aq) + 2 OH⁻ (aq)
___s_________s________2s

Ksp = (s)(2s)²
Ksp = 4s³
Ksp = 4(5 x 10⁻⁵)³
Jadi Ksp = 5 x 10⁻¹³

[5]
(a) Ca(OH)₂ (s) ⇄ Ca²⁺ (aq) + 2 OH⁻ (aq)
_____a_________a________2a

Ksp = (a)(2a)²
Ksp = 4a³

(b) Ag₂CrO₄ (s) ⇄ 2 Ag⁺ (aq) + CrO₄²⁻ (aq)
_____a_________2a________a

Ksp = (2a)²(a)
Ksp = 4a³

(c) Ca₃(PO₄)₂ (s) ⇄ 3 Ca²⁺ (aq) + 2 PO₄³⁻ (aq)
_____a_________3a________2a

Ksp = (3a)³(2a)²
Ksp = 108a⁵