Buffer Lab Methods & Results Methods Four test tubes were labeled A through D, with 5 mL of distilled water placed in test tubes A and B, and 5 mL of a buffer solution placed in test tubes C and D. Using separate strips of pH paper, the pH of each test tube was determined. After the initial observations, 5mL of 0.1M hydrochloric acid was added to test tubes A and C. The solutions were mixed and then the pH was tested. With test tubes B and D, 5 mL of 0.1M sodium hydroxide was added, mixed, and the resulting pH was tested. This procedure was then repeated substituting 0.1M acetic acid for the hydrochloric acid and 0.1M ammonium hydroxide for the sodium hydroxide. Results Table 1- Initial pH Substance pH Water 7 Buffer solution 6. Table 2-pH of solution after the addition of an acid or base Solution pH Water and HCI Buffer and HCI Water and NaOH Buffer and NaOH Water and HC,H.O. Buffer and HOНО. Watcr and NHLOH Buffer and NILOI 12 11 4. 6. 10

Buffer Lab Methods & Results Methods Four test tubes were labeled A through D, with 5 mL of distilled water placed in test tubes A and B, and 5 mL of a buffer solution placed in test tubes C and D. Using separate strips of pH paper, the pH of each test tube was determined. After the initial observations, 5mL of 0.1M hydrochloric acid was added to test tubes A and C. The solutions were mixed and then the pH was tested. With test tubes B and D, 5 mL of 0.1M sodium hydroxide was added, mixed, and the resulting pH was tested. This procedure was then repeated substituting 0.1M acetic acid for the hydrochloric acid and 0.1M ammonium hydroxide for the sodium hydroxide. Results Table 1- Initial pH Substance pH Water 7 Buffer solution 6. Table 2-pH of solution after the addition of an acid or base Solution pH Water and HCI Buffer and HCI Water and NaOH Buffer and NaOH Water and HC,H.O. Buffer and HOНО. Watcr and NHLOH Buffer and NILOI 12 11 4. 6. 10

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter15: Acid–base Equilibria

Section: Chapter Questions

Problem 57P

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When 40.00 mL of a weak monoprotic acid solution is titrated with 0.100-M NaOH, the equivalence point is reached when 35.00 mL base has been added. After 20.00 mL NaOH solution has been added, the titration mixture has a pH of 5.75. Calculate the ionization constant of the acid.
2. If an acetic acid/sodium acetate buffer solution is prepared from 100. mL of 0.10 M acetic acid what volume of 0.10 M sodium acetate must be added to have a pH of 4.00? 100. mL 50. mL 36 mL 18 mL
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