14. Acid Base questions

Michael Mombourquette

  1. Calculate [OH–] in a solution where [H+]=3.5×10-4.  assume Kw=1×10-14.    [2.8×10-11 M]
  2. The acid dissociatio constant for butanoic acid, C3H7COOH, is Ka=1.5×10-5 at 25 ºC.  Calculate the base dissociation constant Kb for the butanoate ion C3H7COO–.                                                [6.7×10-10]
  3. Calculate [H+], [CH3COO–], [CH3COOH], and [OH–] in a 0.0015 M solution of acetic acid, CH3COOH.
    [1.5×10-4 M, 1.5×10-4 M, 0.0014 M, 6.7×10-11 M]
  4. Calculate [OH–], [NH4+], [NH3], and [H+] in a 0.007 M solution of ammonia.
    [3.5×10-4 M, 3.5×10-4 M, 0.0066 M, 2.9×10-11 M]
  5. If some ammonia is added to a solution of 0.15 M acetic acid, does [CH3COOH] increase, decrease, or stay the same? Explain.
  6. what it the pH of a 0.45 M solution of benzoic acid?                                          [2.3]
  7. A 0.10 M solution of an acid has a pH of 3.5. What it the pKa of that acid?    [6.0]
  8. Make a sketch of the distribution diagram for methylamine, CH3NH2, in aqueous solution and label your diagram appropriately.
  9. Calculate the pH of each of the following solutions:
    1. 0.025 M acetic acid                                                                                                 [3.2]
    2. 0.080 M nitrous acid                                                                                              [2.2]
    3. 0.015 M ammonia                                                                                                  [10.7]
    4. 0.015 M ammonium chloride                                                                               [5.5]
  10. sketch a distribution diagram for nitrous acid HNO2. mark on it the approximate pH you would expect for each of the following solutions
    1. a solution of approximately 0.1 M nitrous acid
    2. a solution of approximately 0.1 M sodium nitrite
    3. butter solution containing approximately equal amounts of nitrous acid and sodium nitrite.
  11. Calculate the pH of the following solutions
    1. 0.080 M HCl                                                                                                                 [1.1]
    2. 0.15 M acetic acid                                                                                                       [2.8]
    3. 0.050 M HCN                                                                                                              [5.2]
    4. 0.45 M ammonia                                                                                                       [11.4]
    5. 0.15 M sodium acetate                                                                                              [9.0]
    6. 0.20 M sodium oxalate, Na2C2O4.                                                                          [8.7]
  12. What is the concentration of acetic acid that has a pH of 3.00?                          [0.060 M]
  13. 0.50 mol of potassium hydrogen phosphate, K2HPO4, is dissolved in 1.0 L of water.
    1. sketch a distribution diagram for the phosphoric acid system.
    2. calculate the pH and [PO43-] in the solution                                              [9.8, 1.5×10-3 M]
    3. calculate the pH after 0.65 mol of HCl is added to the solution.                   [2.5]
  14. Calculate hte pH of each of teh following solution made by adding enough water to make a solution with the indicated concentrations:
    1. 0.15 M acetic acid and 0.50 M sodium acetate.                                                     [5.3]
    2. 0.15 M acetic acid and 0.050 M sodium hydroxide                                               [4.4]
    3. 0.15 M acetic acid and 0.20 M ammonium chloride                                             [1.8]
    4. 0.10 M ammonia and 0.20 M ammonium chloride                                               [8.9]
  15. A 0.10 M solution of an acid has a pH of 3.5.  what is the pKa of this monoprotic acid?   [6.0]
  16. What is the pH of a solution of 0.25 M potassium dihydrogen phosphate?           [4.7]

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

First Year General Chemistry Copyright © 2020 by Michael Mombourquette is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book