what is the concentration of the hydroxide ion in a solution if .12 mol of strontium hydroxide are dissolved in water and the final solution volume is 500. mL?
From the problem I assume all of the 0.12 mol Sr(OH)2 is dissolved.
Sr(OH)2 ==> Sr^2+ + 2OH^-
0.12 mol/0.5L = 0.24M
Therefore, )Sr^2+) = 0.24M
(OH^-) = 2*0.24M = 0.48 M.