Ionic Equilibrium

[Abdul Quadeer]

1. The problem statement, all variables and given/known data

Caculate the pH at which Magnesium Hydroxide begins to precipitate
from a solution containing 0.1M Mg2+ ion? Ksp=10^-11

2. Relevant equations



3. The attempt at a solution

I did not understand why Ksp is given.
Since the concentration of Mg2+ is 0.1, concentration of OH- will be 0.2 (by stoichiometry).
Moreover there is no other source of OH-.
Where am I wrong?

[Borek]

You start with a solution that contains Mg2+ (from whatever source) and you add base till precipitation starts.

Your ability to understand questions in unintended way is incredible :rofl:

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[Abdul Quadeer]

LOL. May be it is because I think too much behind a problem :wink: