Final answer:
The pH of a saturated solution of Ca(OH)2 is calculated based on its molar solubility. The molar solubility of Ca(OH)2 gives us the concentration of OH- ions, which is used to calculate the pOH and subsequently the pH, resulting in a value close to 12.14.
Step-by-step explanation:
To calculate the pH of a saturated solution of Ca(OH)₂, we need to first know its molar solubility. According to provided data, the molar solubility of Ca(OH)₂ is 6.9 × 10⁻³ M.
Because Ca(OH)₂ dissociates into Ca²⁺ and two OH⁻ ions, the concentration of OH⁻ ions will be twice the concentration of Ca(OH)₂, which is 2 × 6.9 × 10⁻³ M = 1.38 × 10⁻² M.
We can then use this concentration to calculate the pOH:
pOH = -log[OH⁻] = -log(1.38 × 10⁻²) ≈ 1.86
Now, using the relationship between pH and pOH, pH + pOH = 14:
pH = 14 - pOH = 14 - 1.86 = 12.14
Thus, the pH of a saturated solution of Ca(OH)₂ is close to 12.14, which means that the correct answer is (d) 12.13.