The following is list of weak acids and their pka values weak acid „pKa benzoic acid 4.20 hydrogen citrate 6.40 hydrocyanic acid 9.31 hydrogen phosphate 12.38 Which would be the best buffer to use at pH 7? For benzoic acid, a 50:50 mixture of benzoic acid and its conjugate base, the benzoate ion, would have pH = The buffering capacity of a benzoic acid:benzoate buffer would be at pH = 7 А. 4.20 В. 6.40 С. 9.31 E. benzoic acid F. hydrogen citrate D. 12.38 G. hydrocyanic acid H. hydrogen phosphate I. good J. bad

The following is list of weak acids and their pka values weak acid „pKa benzoic acid 4.20 hydrogen citrate 6.40 hydrocyanic acid 9.31 hydrogen phosphate 12.38 Which would be the best buffer to use at pH 7? For benzoic acid, a 50:50 mixture of benzoic acid and its conjugate base, the benzoate ion, would have pH = The buffering capacity of a benzoic acid:benzoate buffer would be at pH = 7 А. 4.20 В. 6.40 С. 9.31 E. benzoic acid F. hydrogen citrate D. 12.38 G. hydrocyanic acid H. hydrogen phosphate I. good J. bad

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter15: Acid-base Equilibria

Section: Chapter Questions

Problem 4RQ: A good buffer generally contains relatively equal concentrations of weak acid and conjugate base. If...

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You have a solution of the weak acid HA and add some of the salt NaA to it. What are the major species in the solution? What do you need to know to calculate the pH of the solution, and how would you use this information? How does the pH of the solution of just the HA compare with that of the final mixture? Explain.
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Malic acid is a weak diprotic organic acid with Ka1 = 4.0 104 and Ka2 = 9.0 105. a Letting the symbol H2A represent malic acid, write the chemical equations that represent Ka1 and Ka2. Write the chemical equation that represents Ka1 Ka2. b Qualitatively describe the relative concentrations of H2A, HA, A2, and H3O+ in a solution that is about one molar in malic acid. c Calculate the pH of a 0.0175 M malic acid solution and the equilibrium concentration of [H2A]. d What is the A2 concentrationin in solutions b and c?
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