Question

For the buffer we prepared in the procedure, when the buffering effect fail? (Hint: This is equivalent to asking when will we exceed the buffer's capacity?)

Procedure I. Obtain a pH meter and calibrate it if necessary ll. Acids comparison a. Prepare 100 milliliters of an aqueous solution of oxalic acid dihydrate at a concentration 0.010 M b. Determine the pH of the resulting solution. c. Repeat parts a and b on the same volume of solution atthe same concentration for formic acid, acetic acid, and citric acid. d. Compare the relative acidities of the acids. Ill. Buffer Effect a. Unbuffered solution i. Place 50 mL of deionized water into a 100 mL beaker. ii. Using a disposable plastic pipette, transfer 1.0 mL of 6 M aqueous hydrochloric acid into the beaker. iii. Determine the pH ofthe solution. iv. Add an additional 1.0 mL of 6 M HCl and check the pH again v. Repeat this procedure until you have added a total of 10. mL b. Prepare an acetate buffer i. Place 100 mL of 1.0 M acetic acid and 100 mL of 1.0 M sodium acetate into a 250 mL beaker and stir well. ii. As described above for the unbuffered solution, add 1.0 m portions of 6 M HCl and check the pH after each addition.

Answer 1

For the buffer we prepared in the procedure, when the buffering effect fail? (Hint: This is equivalent to asking when will we exceed the buffer's capacity?) 0 A. Upon the addition of the first 1 mL of 6M HCl. O B. After the addition of 10 mL of 6 M aq. HCl. ° C. After the addition of 16.7 mL of 6 M aq. HCI. D. Never. Which of the following carboxylic acids is the strongest in aqueous solution? Hint: Consult a pKa table if your empirical data isn't clear. O A. Oxalic acid B. Formic acid C. Acetic acid O D. Citric acid