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6-2.Equilibrium-II (Ionic Equilibrium)
hard
જો $Mg(OH)_2$ નું સંતૃપ્ત દ્રાવણનું $4 \times 10^{-12} \,K_{sp}$ હોય તો $pH$ $=......$
A
$11.5$
B
$10.3$
C
$12.1$
D
$14.8$
Solution
$Mg(OH)_2 \rightleftharpoons Mg^{+2} + 2OH^-$
$ 1$ $s$ $2s$
$K_{sp} = 4s^2 ⇒ 4 \times 10^{-12} = 4s^3 ⇒ 10^{-12} = s^3 ⇒ s = (10^{-12})^{1/3} = 10^{-4}$
$OH^- = 2s = 2 \times 10^{-4}$
$pOH = -log (2 \times 10^{-4}) = -log 2 + 4 = – 0.3010 + 4 = 3.7$
$pH = 14 – 3.7 = 10.3$
Standard 11
Chemistry