Question

PLEASE ANSWER ALL PARTS OF THE BOTTOM PART B

B. Calcium Hydroxide Titration

1. Use a pipet to withdraw 20.00 mL of a saturated solution of Ca(OH)₂ and place it in a 150 mL Erlenmeyer flask.
2. Add three drops of phenolphthalein indicator.
3. Fill the buret to the zero mL mark with 0.10 M HCl solution and titrate the hydroxide solution until the mixture turns colorless.   
4. Record the buret reading at the end point.
5. Repeat steps 1- 4. Remember to re-fill the buret between titrations if needed and to record initial and final buret readings for each titration.
6. Run a third titration if the first two runs are different by more than 2%.

DISPOSAL: Dispose of the remaining HCl solutions and the reaction mixtures in the sink. Run some tap water afterwards.

B. Titration of Ca(OH)₂ solution

Trial 1                          Trial 2                      Trial 3

1. Volume of Ca(OH)₂          __10.0 mL__              __10.0 mL_                 __10.0 mL_

2. Initial buret reading         _ __0.0 mL__               ___11.2 mL_                __21.0 mL _

3. Final buret reading              _11.2 mL__             ___21.0 mL_               ___30.7 mL__

4. Volume of HCl needed         _________                 ___________              _________

5. Moles HCl                             __________             ___________              _________

6. Moles of OH^-                      ____________            ____________            ___________

7. Molarity of OH^-                 ____________            __________                _________

(Show your calculations)

8. Average Molarity of OH^- (mol/L)             _______________________

9. K_sp of Ca(OH)₂: ________________

(Show your calculations)

Answer 1