Guide Questions for E7

Preparation of Saturated Ca(OH)2 solution

1. What was the indicator that a saturated solution had already been prepared?2. Why is it important to filter the solution?

Titrimetric Analysis

3. What is the initial color of the solution when phenolphthalein was added? Why is it so?4. What is the color at the endpoint of titration?

Data Analysis

5. Express Ksp in terms of the molar solubility of Ca(OH)2.6. Solve for the [OH-] in each solution.7. From the computed [OH-], solve for the [Ca2+].8. From the data obtained from saturated solution with water as solvent, solve for the Ksp of the Ca(OH)2. Compare the experimental to the theoretical value of Ksp. 9. Compare the solubility of Ca(OH)2 in 0.5 M KCl solution to the solubility in water. Provide an explanation to the experimental result.10. Compare the solubility of Ca(OH)2 in 0.1 M Ca(NO3)2 solution to the solubility in water. Provide an explanation to the experimental result. 11. Calculate for the theoretical solubility of Ca(OH)2 in 0.1M Ca(NO3)2 and compare it to your experimental data.12. Give all possible sources of errors, determine which parameter will be affected, and determine whether it would give a positive or a negative error. Tabulate.