When 400ml of a 0.01M MgCl2 solution is mixed with a 300ml if a NaOH solution at pH 9.0, a precipitate will form. True or False?

Answer 1

(Mg^2+) = 0.01 x (400/700) = ?
pH of NaOH = 9 so pOH is 14-9 = 5 and (OH^-) = 1E-5M initially. After dilution it is
1E-5 x (300/700) = ?

Qsp = (Mg^2+)(OH^-)^2. Plug in the numbers to calculate Qsp then compare with Ksp for Mg(OH)2. If Qsp > Ksp a ppt will form.
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