Multiple Choice
Identify the choice that best completes the statement or answers
the question.
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1.
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Calculate the
[H3O+] in 0.010 M HOCl solution. Ka = 3.5 x
10-8.
a. | 1.9 x 10-5 M | b. | 3.6 x 10-5 M | c. | 5.8 x
10-5 M | d. | 4.0 x
10-6 M | e. | 7.2 x
10-6 M |
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2.
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In the laboratory, a general chemistry student
measured the pH of a 0.599 M aqueous solution of ethylamine, C2H5NH2
(a weak base), to be 12.192. Use the information she obtained to determine the Kb for this
base.
a. | 2.41 x 10-11 | c. | 4.15 x 10-4 | b. | 10-1.88 | d. | 1.56 x
10-2 |
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3.
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The pOH of an aqueous solution of 0.500 M
trimethylamine (a weak base, Kb = 6.3 x 10-5) with the formula
(CH3)3N) is:
a. | 9.8 | b. | 7 | c. | 4.2 | d. | 2.25 | e. | less than
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4.
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What is the [H3O+]
of a solution that is 0.0100 M in HNO2 (Ka = 4.5 x 10-4 ) and 0.0100
M in NaNO2?
a. | 2.14 x 10-4 M | b. | 1.45 x 10-4 M | c. | 7.41 x
10-4 M | d. | 4.5 x
10-4 M | e. | 1.17 x
10-4 M |
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5.
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When a weak acid is titrated with a strong base,
the pH at the equivalence point is ALWAYS __________.
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6.
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Calculate the pH for a buffer solution prepared by
mixing 100. mL of 0.10 M HF and 200. mL of 0.10 M KF.
a. | 2.82 | b. | 2.96 | c. | 3.32 | d. | 3.44 | e. | 3.53 |
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7.
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Which of the following aqueous solutions are good
buffer systems?
I. 0.20 M calcium hydroxide + 0.20 M calcium
chloride
II. 0.35 M ammonia + 0.32 M ammonium nitrate
III. 0.10 M hypochlorous acid + 0.14 M
hydrobromic acid
IV. 0.33 M barium iodide + 0.27 M sodium iodide
V. 0.29 M hydrochloric acid +
0.19 M sodium chloride
a. | II III, and IV | b. | II and V | c. | I and
IV | d. | II | e. | All would be good
buffers |
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8.
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How many grams of solid sodium acetate should be
added to 1.50 L of a 0.287 M acetic acid solution to prepare a buffer with a pH of 4.140 ? Grams
sodium acetate = ?
a. | 2.43 g | c. | 4.14.g | b. | 8.77
g | d. | 8.00 g |
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9.
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Which salt dissolved in water will give the highest
pH?
a. | NaCl | b. | KBr | c. | NaNO3 | d. | NH4Cl | e. | NaF |
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10.
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The Ka of the weak acid HNO2
is 7.4 x 10-4. What is the Kb of its conjugate base,
NO2-?
a. | 7.4 x 10-4 | b. | 1.35 x 103 | c. | 1.35 x
10-11 | d. | 1.0 x
10-14 | e. | 1.8 x
10-5 |
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11.
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What is the pH of 0.10 M sodium acetate (NaAc)
solution? The Ka of acetic acid (HAc) is 1.8 x 10-5.
a. | 1.0 | b. | 0.10 | c. | 7.0 | d. | 8.9 | e. | 5.1 |
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