Chapter 17: Buffers, Ksp etc.
Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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The pH of a solution that contains 0.818 M acetic acid (Ka = 1.76
´ 10-5) and 0.172 M sodium acetate is __________.
a. | 4.077 | b. | 5.434 | c. | 8.571 | d. | 8.370 | e. | 9.922 |
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2.
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The Ka of acetic acid is 1.76 ´
10-5. The pH of a buffer prepared by combining 50.0 mL of 1.00 M potassium acetate and
50.0 mL of 1.00 M acetic acid is __________.
a. | 1.705 | b. | 0.851 | c. | 3.406 | d. | 4.754 | e. | 2.383 |
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3.
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Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid
(HCO2H) and 0.230 mol of sodium formate (NaCO2H) in water sufficient to yield
1.00 L of solution. The Ka of formic acid is 1.77 ´
10–4.
a. | 2.099 | b. | 10.463 | c. | 3.546 | d. | 2.307 | e. | 3.952 |
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4.
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A 25.0 mL sample of 0.723 M HClO4 is titrated with a 0.273 M KOH
solution. What is the [H+] (molarity) before any base is added?
a. | 0.439 | b. | 1.00 ´
10-7 | c. | 0.723 | d. | 2.81 ´
10-13 | e. | 0.273 |
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5.
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The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of
0.125 M HCl is __________.
a. | 6.29 | b. | 7.00 | c. | 8.11 | d. | 5.78 | e. | 0.00 |
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6.
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The solubility of lead (II) chloride (PbCl2) is 1.6 ´ 10–2 M. What is the Ksp of
PbCl2?
a. | 5.0 ´ 10-4 | b. | 4.1 ´ 10-6 | c. | 3.1 ´
10-7 | d. | 1.6 ´ 10-5 | e. | 1.6 ´ 10-2 |
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7.
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Which one of the following pairs cannot be mixed together to form a
buffer solution?
a. | NH3, NH4Cl | b. | NaC2H3O2, HCl
(C2H3O2- = acetate) | c. | RbOH,
HBr | d. | KOH, HF | e. | H3PO4,
KH2PO4 |
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8.
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What change will be caused by addition of a small amount of HCl to a solution
containing fluoride ions and hydrogen fluoride?
a. | The concentration of hydronium ions will increase significantly. | b. | The concentration of
fluoride ions will increase as will the concentration of hydronium ions. | c. | The concentration of
hydrogen fluoride will decrease and the concentration of fluoride ions will
increase. | d. | The concentration of fluoride ion will decrease and the concentration of hydrogen
fluoride will increase. | e. | The fluoride ions will precipitate out of
solution as its acid salt. |
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9.
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Of the following solutions, which has the greatest buffering capacity?
a. | 0.821 M HF and 0.217 M NaF | b. | 0.821 M HF and 0.909 M NaF | c. | 0.100 M HF and 0.217
M NaF | d. | 0.121 M HF and 0.667 M NaF | e. | They are all buffer solutions and would all
have the same capacity. |
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10.
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Which of the following could be added to a solution of sodium acetate to produce
a buffer?
a. | acetic acid only | b. | acetic acid or hydrochloric
acid | c. | hydrochloric acid only | d. | potassium acetate only | e. | sodium chloride or
potassium acetate |
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11.
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A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M
NaOH solution. The titration curve above was obtained. The unknown compound is __________.
a. | a strong acid | b. | a strong base | c. | a weak
acid | d. | a weak base | e. | neither an acid nor a
base |
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12.
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A 25.0 mL sample of a solution of a monoprotic acid is titrated with a 0.115 M
NaOH solution. The titration curve above was obtained. The concentration of the monoprotic acid is
about __________ mol/L.
a. | 25.0 | b. | 0.0600 | c. | 0.240 | d. | 0.120 | e. | 0.100 |
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13.
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A 25.0 mL sample of a solution of a monoprotic acid is titrated with a 0.115 M
NaOH solution. The titration curve above was obtained. Which of the following indicators would be
best for this titration?
a. | methyl red | b. | bromthymol blue | c. | thymol
blue | d. | phenolpthalein | e. | bromocresol
purple |
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14.
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In which of the following aqueous solutions would you expect AgCl to have the
highest solubility?
a. | pure water | b. | 0.020 M BaCl2 | c. | 0.015
NaCl | d. | 0.020 AgNO3 | e. | 0.020 KCl |
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