18. Let’s consider calcium hydroxide, Ca(OH)2 which has Ksp = 5.02 x 10–6 . a. What is the pH of a saturated solution of Ca(OH)2 in water at 25 o C? b. Is Ca(OH)2(s) more soluble in acidic or basic solutions? Briefly explain your reasoning. c. Let’s say you have a 0.5M aqueous solution of CaCl2. What concentration of hydroxide (OH– ) is needed to begin precipitation of Ca(OH)2(s) at 25o C? d. If you have an aqueous solution with a pH buffered at 11.4, what concentration of Ca2+(aq) is needed to begin precipitation of Ca(OH)2 (s) at 25o C?