What is the pOH (nearest integer) of a saturated solution of Ca(OH)2? The solubility of Ca(OH)2 is 1.50kgm−3 at 25oC. Assume 100% dissociation.
Open in App
Solution
The solubility S of calcium hydroxide is 1.50 kgm−3 or 1.50 gL−1. Convert the unit of solubility in moles per litre. 1.50gL−174.1gmol−1=0.020MolL−1. Th hydroxide ion concentration is twice its solubility. [OH−=2S=2×0.020M=0.040M. The pOH of the solution is pOH=−log[OH−]=−log0.040=1.393. The pH of the solution is pH=14−pOH=14−1.393=12.607. Hence, the pH of the solution is 12.607.