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Grade 12th passPhysical Chemistry

The Ksp of Mg(OH)2 is 8.9 10-12 at 25*C. If the pH of solution is adjusted to 9.0 . How much Mg+2 ion will be precipitated as Mg(OH)2 from a 0.1 M MgCl2 solution at 25*C ? Assume that MgCl2 is completely dissociated.
​ a. 0.011
​b. 0.089
c. 0.11
d. 0.89
Please explain in detail.............

Profile image of RATHER YASIR
7 Years agoGrade 12th pass
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1 Answer

Profile image of Vikas TU
6 Years ago
Ksp[Mg(OH)2]=8.9×10^−2 
pH=9
[H+]=10^−9
[OH−]=10^−5
Ksp=[Mg2+][OH−]^2
8.9×10^−12=[Mg2+][10^−5]^2
[Mg2+]=8.9×10^−2=0.089
Conc. Of Mg2+ precipitated =0.1−0.089
=0.011mol/L.t