. Calcium hydroxide, Ca(OH)2, dissolves in water at 25 °C to the extent of 1.78 g L−1. What is the value of the solubility product Ksp of calcium hydroxide in water at that temperature? The molar mass of Ca(OH)2 is 74.093 g mol−1. A) 22.5 B) 1.39 × 10−5 C) 0.187 D) 5.55 × 10−5 E) 5.77 × 10−4