A 22.0 mL sample of 0.124 mol L- diprotic acid (H,A) solution is titrated with 0.1021 mol L-' KOH The acid ionization constants for the acid are K. = 5.2 x 10 5 and K = 3.4 x 10 10 Part A At what added volume of base does the first equivalence point occur? ? V = mL Submit Request Answer Part B At what added volume of base does the second equivalence point occur? DA V = mL Submit Request Answer

A 22.0 mL sample of 0.124 mol L- diprotic acid (H,A) solution is titrated with 0.1021 mol L-' KOH The acid ionization constants for the acid are K. = 5.2 x 10 5 and K = 3.4 x 10 10 Part A At what added volume of base does the first equivalence point occur? ? V = mL Submit Request Answer Part B At what added volume of base does the second equivalence point occur? DA V = mL Submit Request Answer

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter15: Additional Aqueous Equilibria

Section: Chapter Questions

Problem 93QRT: When 40.00 mL of a weak monoprotic acid solution is titrated with 0.100-M NaOH, the equivalence...

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Sketch a pH curve for the titration of a weak acid (HA) with a strong base (NaOH). List the major species, and explain how you would go about calculating the pH of the solution at various points, including the halfway point and the equivalence point.
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.
Potassium hydrogen phthalate, known as KHP (molar mass = 204.22 g/mol), can be obtained in high purity and is used to determine the concentration of solutions of strong bases by the reaction HP(aq)+OH(aq)H2O(l)+P2(aq) If a typical titration experiment begins with approximately 0.5 g KHP and has a final volume of about 100 mL, what is an appropriate indicator to use? The pKa for HP is 5.51.
Consider the following pH curves for 100.0 mL of two different acids with the same initial concentration each titrated by 0.10 M NaOH. a. Which plot represents a pH curve of a weak acid, and which plot is for a strong acid? How can you tell? Cite three differences between the plots that help you decide. b. In both cases the pH is relatively constant before the pH changes greatly. Does this mean that at some point in each titration each solution was a buffered solution? c. True or false? The equivalence point volume for each titration is the same. Explain your answer. d. True or false? The pH at the equivalence point for each titration is the same. Explain your answer.
The titration of 0.100 M acetic acid with 0.100 M NaOH is described in the text. What is the pH of the solution when 35.0 mL of the base has been added to 100.0 mL of 0.100 M acetic acid?
Marble is almost pure CaCO3. Acid rain has a devastating effect on marble statuary left outdoors. Assume that the reaction which occurs is CoCO3(s)+ H+(aq)Ca2+(aq)+HCO3(aq) Neglecting all other competing equilibria and using Tables 15.1 and 13.2, calculate (a) K for the reaction. (b) the molar solubility of CaCO3 in pure water. (c) the molar solubility of CaCO3 in acid rainwater with a pH of 4.00.
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.
Aniline hydrochloride, (C6H5NH3)Cl, is a weak acid. (Its conjugate base is the weak base aniline, C6H5NH2.) The acid can be titrated with a strong base such as NaOH. C6H5NH3+(aq)+OH(aq)C6H5NH2(aq)+H2O(l) Assume 50.0 mL of 0.100 M aniline hydrochloride is titrated with 0.185 M NaOH. (Ka for aniline hydrochloride is 2.4 105.) (a) What is the pH of the (C6H5NH3) solution before the titration begins? (b) What is the pH at the equivalence point? (c) What is the pH at the halfway point of the titration? (d) Which indicator in Figure 17.11 could be used to detect the equivalence point? (e) Calculate the pH of the solution after adding 10.0, 20.0, and 30.0 mL of base. (f) Combine the information in parts (a), (b), (c), and (e), and plot an approximate titration curve.
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Fifty cm3 of 1.000 M nitrous acid is titrated with 0.850 M NaOH. What is the pH of the solution (a) before any NaOH is added? (b) at half-neutralization? (c) at the equivalence point? (d) when 0.10 mL less than the volume of NaOH to reach the equivalence point is added? (e) when 0.10 mL more than the volume of NaOH to reach the equivalence point is added? (f) Use your data to construct a plot similar to that shown in Figure 14.10 (pH versus volume NaOH added).
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Consider the nanoscale-level representations for Question 110 of the titration of the aqueous weak acid HX with aqueous NaOH, the titrant. Water molecules and Na+ ions are omitted for clarity. Which diagram corresponds to the situation: After a very small volume of titrant has been added to the initial HX solution? When enough titrant has been added to take the solution just past the equivalence point? Halfway to the equivalence point? At the equivalence point? Nanoscale representations for Question 110.