The solubility product of Mg(OH)2 at 25 °C is Ksp=1.8×10−11. What is the approximate molar solubility of Mg(OH)2 in a solution buffered and maintained at pH 12? (Assume activity coefficients are 1 and the pH remains constant as the solid dissolves.)
a) 1.6×10−4M
b) 1.8×10−9M
c) 1.8×10−7M
d) 5.3×10−4M