Question #885cc

1 Answer
Apr 27, 2015

[OH] =105

From Ksp of Cu(OH)2, it starts precipitating at:
2.21020 = [Cu2+]*[OH]2
[OH]=0.221020=0.461010

and from Ksp of Mg(OH)2, it starts precipitating at
6.31010 =[Mg2+]*[OH]2
[OH]=1.261010 =1.12105

therefore at [OH]=105 all Cu(OH)2 is precipitated and all Mg(OH)2 is in solution