Calculate the threshhold in which Co (OH)_3 given a Ksp= 0.0000000000000199 would increase in solubility. Is the pH greater than, less than, or equal to?

Question

Calculate the threshhold in which Co (OH)_3 given a Ksp= 0.0000000000000199 would increase in solubility. Is the pH greater than, less than, or equal to?

Answer 1

OK,

For starters, this question is vague and disorganized. No definite "threshold" exists. Solid Co(OH)₃ (we'll assume that is the species, since you didn't indicate an oxidation state!) will be in equilibrium with the surrounding solution, no matter what the pH. Obviously, if you decrease the pH, the ambient (OH)(-) concentration decreases, which will "pull" some solid into solution. If you couldn't figure that out qualitatively, you might profit from some tutoring time?

Also, when you quote a K_sp , writing it in scientific notation is customary. Noone wants to count all those zeros, too easy to make mistakes that way.