A buffer contains a weak acid, HA, and its conjugate base, A". The weak acid has a pKa = 3.72. Ifthe pH is 4.40, thenSelect one:a. [HA] > [A]b. [HA] <[A]c. [HA] = [A]d. more than one of thesee. the pH is outside of the suitable buffer range and the solution is not buffered effectively

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Answered: A buffer contains a weak acid, HA, and…

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 2ALQ: A friend asks the following: Consider a buffered solution made up of the weak acid HA and its salt...

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A good buffer generally contains relatively equal concentrations of weak acid and conjugate base. If you wanted to buffer a solution at pH = 4.00 or pH = 10.00, how would you decide which weak acidconjugate base or weak baseconjugate acid pair to use? The second characteristic of a good buffer is good buffering capacity. What is the capacity of a buffer? How do the following buffers differ in capacity? How do they differ in pH? 0.01 M acetic acid/0.01 M sodium acetate 0.1 M acetic acid/0.1 M sodium acetate 1.0 M acetic acid/1.0 M sodium acetate
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.
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The species called glacial acetic acid is 98% acetic acid by mass (d=1.0542g/mL). What volume of glacial acetic acid must be added to 100.0 mL of 1.25 M NaOH to give a buffer with a pH of 4.20?
A 10.00-g sample of the ionic compound NaA, where A is the anion of a weak acid, was dissolved in enough water to make 100.0 mL of solution and was then titrated with 0.100 M HCl. After 500.0 mL HCl was added, the pH was 5.00. The experimenter found that 1.00 L of 0.100 M HCl was required to reach the stoichiometric point of the titration. a. What is the molar mass of NaA? b. Calculate the pH of the solution at the stoichiometric point of the titration.
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Sketch the titration curve for a weak acid titrated by a strong base. When performing calculations concerning weak acidstrong base titrations, the general two-slep procedure is to solve a stoichiometry problem first, then to solve an equilibrium problem to determine the pH. What reaction takes place in the stoichiometry part of the problem? What is assumed about this reaction? At the various points in your titration curve, list the major species present after the strong base (NaOH, for example) reacts to completion with the weak acid, HA. What equilibrium problem would you solve at the various points in your titration curve to calculate the pH? Why is pH 7.0 at the equivalence point of a weak acid-strong base titration? Does the pH at the halfway point to equivalence have to be less than 7.0? What does the pH at the halfway point equal? Compare and contrast the titration curves for a strong acidstrong base titration and a weak acidstrong base titration.
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Define a buffer solution. What makes up a buffer solution? How do buffers absorb added H+ or OH with little pH change? Is it necessary that the concentrations of the weak acid and the weak base in a buffered solution be equal? Explain. What is the pH of a buffer when the weak acid and conjugate base concentrations are equal? A buffer generally contains a weak acid and its weak conjugate base, or a weak base and its weak conjugate acid, in water. You can solve for the pH by setting up the equilibrium problem using the K.a reaction of the weak acid or the Kb reaction of the conjugate base. Both reactions give the same answer for the pH of the solution. Explain. A third method that can be used to solve for the pH of a buffet solution is the HendersonHasselbalch equation. What is the HendersonHasselbalch equation? What assumptions are made when using this equation?
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A buffer contains a weak acid, HA, and its conjugate base, A". The weak acid has a pKa = 3.72. If the pH is 4.40, then Select one: a. [HA] > [A] b. [HA] <[A] c. [HA] = [A] d. more than one of these e. the pH is outside of the suitable buffer range and the solution is not buffered effectively