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SOMEONE PLEASE EXPLAIN AND ANSWER THIS QUESTION :

Will Co(OH)2 precipitate from solution if the pH of a 0.034 M solution of Co(NO3)2 is adjusted to 9.45? (Ksp of Co(OH)2 is 1.3 10-15)

Support your answer by calculating the ion product (Q) of the Co(OH)2 solution.

2 answers

Co(OH)2 will ppt if Q > Ksp =1.3E-15
Q = (Co^2+)(OH^-)^2
(Co^2+) = 0.034 from the problem.
(OH^-) = from pH 9.45
pH = 9.45, pOH = 4.55
4.55 = -log(OH^-)
(OH^-) = 2.82E-5
Q = (0.034)(2.82E-5)^2 = 2.7E-11
If Q > Ksp, Co(OH)2 will ppt.
If Q < Ksp, Co(OH)2 will not ppt.
THANX!!!