Chapter Three
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
1. A Brønsted-Lowry acid is defined as a ____ and a Brønsted-Lowry base is defined as a
____.
A) proton acceptor, proton donor
B) proton donor, proton donor
C) proton acceptor, proton acceptor
D) proton donor, proton acceptor
E) None of these
Ans: D
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
2. Provide a definition of a Brønsted-Lowry acid.
Ans: A Brønsted-Lowry acid is a proton donor.
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
3. Provide a definition of a Brønsted-Lowry base.
Ans: A Bronsted-Lowry base is a proton acceptor.
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
4. For the following reaction, which reactant functions as an acid?
O
O
+
+
O
I
OH
II
A) I
B) II
C) neither
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
5. For the following reaction, which reactant functions as a base?
O
O
+
+
O
I
OH
II
A) I
B) II
C) neither
Ans: A
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
6. For the following reaction, which reactant functions as an acid?
H2SO4
+
I
O
II
O
+
HSO4
H
A) I
B) II
C) neither
Ans: A
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
7. For the following reaction, which reactant functions as a base?
H2SO4
I
+
O
II
O
H
A) I
B) II
C) neither
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
+
HSO4
8. For the following reaction, which reactant functions as a base?
H
Cl
I
+
H
OH
II
O
+
Cl
H
A) I
B) II
C) neither
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Medium
9.
A)
B)
C)
D)
E)
Which of the following is not a Bronsted-Lowry acid?
CH3OH
CH3CH3
CH3NH2
CH3SH
None of these
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Medium
10.
A)
B)
C)
D)
E)
Which of the following is not a Bronsted-Lowry base?
CH3OH
CH3OCH3
CH3NH2
CH3CH3
None of these
Ans: D
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
11.
A)
B)
C)
D)
E)
In a Bronsted-Lowry acid-base reaction the product(s) is (are) a _______.
Lewis acid
conjugate acid only
Lewis acid-base pair
conjugate acid-conjugate base pair
None of these
Ans: D
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
12. In a Brønsted-Lowry acid-base reaction the product(s) is (are) a _______.
Ans: conjugate acid-conjugate base pair
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
13.
A)
B)
C)
D)
E)
A loss of proton from a Brønsted-Lowry acid results in a ___.
Lewis acid
conjugate acid
conjugate base
conjugate acid-base pair
None of these
Ans: C
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
14.
A)
B)
C)
D)
E)
A gain of proton by a Brønsted-Lowry base results in a ___.
Lewis acid
conjugate acid
conjugate base
conjugate acid-base pair
None of these
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
15.
A)
B)
C)
D)
E)
What is the conjugate base of nitric acid?
NO3NO2HNO3
HNO2
None of these
Ans: A
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
16.
A)
B)
C)
D)
E)
What is the conjugate base of phosphoric acid?
HPO42H2PO4HPO32PO43None of these
Ans: B
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
17.
A)
B)
C)
D)
E)
What is the conjugate base of CH3CH2SH?
CH3CH2SCH3CH2CH3CH2SH2+
CH3CH2S2None of these
Ans: A
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
18. Draw the conjugate acid of CH3CH2OH.
Ans:
CH3CH2OH2
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
19. Draw the conjugate acid of CH3OCH3
Ans:
CH3OCH3
H
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Medium
20. Draw the conjugate acid of the following compound.
O
Ans:
OH
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
21. Draw the conjugate base of CH3CCH.
Ans:
H3C
C
C
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Easy
22. Draw the conjugate base of CH3CH2NH2.
Ans:
CH3CH2NH
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Medium
23. Draw the conjugate base of the following compound.
OH
Ans:
O
Topic: Introduction to Brønsted-Lowry Acids and Bases
Section: 3.1
Difficulty Level: Medium
24. Draw the conjugate base of the following compound.
OH
H
O
O
Ans:
H
O
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
25. Which is the conjugate acid in the following reaction?
CH3CH2SH + Na OH
I
A)
B)
C)
D)
E)
II
CH3CH2S Na + H2O
III
IV
I
II
III
IV
Both I & IV
Ans: D
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
26. Which is the conjugate base in the following reaction?
CH3CH2SH + Na OH
I
A)
B)
C)
D)
E)
II
CH3CH2S Na + H2O
III
I
II
III
IV
Both II & III
Ans: C
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
IV
27. Which is the conjugate acid in the following reaction?
+ CH3CH2 Li
N
I
A)
B)
C)
D)
E)
H
H
N
H
IV
III
II
+ CH3CH3 + Li
I
II
III
IV
Both I & IV
Ans: D
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
28. Which is the conjugate base in the following reaction?
+ CH3CH2 Li
N
I
A)
B)
C)
D)
E)
H
H
N
H
III
II
+ CH3CH3 + Li
IV
I
II
III
IV
Both I & III
Ans: C
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
29. For the following reaction label the acid, base, conjugate acid and conjugate base.
CH3CH2SH + Na OH
Ans:
CH3CH2SH + Na OH
acid
base
CH3CH2S Na + H2O
CH3CH2S Na + H2O
conjugate base
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
conjugate acid
30. For the following reaction label the acid, base, conjugate acid and conjugate base.
+ CH3CH2 Li
N
+ CH3CH3 + Li
N
H
H
H
Ans:
+ CH3CH2Li
N
+ CH3CH3
N
H
+ Li
H
H
base
acid
conjugate acid
conjugate base
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
31. For the following reaction label the acid, base, conjugate acid and conjugate base.
+ NaOH
Na
+ H2O
Ans:
+ NaOH
acid
base
Na
conjugate base
+ H2O
conjugate acid
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
32. The tail of the curved arrow must start at ____ electron density and the head must end at
____ electron density.
A) low, high
B) high, high
C) low, low
D) high, low
Ans: D
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
33. Provide a curved arrow mechanism for the following acid-base reaction.
H
+ Na OH
S
S
Na
+ H2O
Ans:
H
S
+ Na OH
Topic: Flow of Electron Density: Curved Arrow Notation
S Na
+ H2O
Section: 3.2
Difficulty Level: Easy
34. Provide a curved arrow mechanism for the following acid-base reaction.
+ Na NH2
+ NH3
Na
Ans:
H
+ Na NH2
Na
+ NH3
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
35. Provide a curved arrow mechanism for the following acid-base reaction.
H
N
H
NH2
+
N
H
H +
NH3
H
Ans:
H
N
H +
NH2
N
H
H +
NH3
H
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
36. Identify the acid and the base and provide a curved arrow mechanism for the following
reaction.
Ans:
O
H
acid
+ Na OH
O
base
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
+ H2O + Na
37. Identify the acid and the base and provide a curved arrow mechanism for the following
reaction.
O
O
+ NH3
+ NaNH2
Na
Ans:
O
O
+ NH3
+ NaNH2
Acid
Na
Base
H
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
38. Identify the acid and the base and provide a curved arrow mechanism for the following
reaction.
Na
+ H2O
+ NaOH
Ans:
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Easy
39. The following reaction mechanism contains error. Which of the following statements
correctly describes the curved arrows consistent with the reaction?
O
O
H
+ Na H
O
O Na
+ H2
A) The curved arrow should start at the carbonyl oxygen atom
B) The curved arrow should start at the hydride, go to the hydrogen connected to oxygen
and a second arrow should start from the O—H covalent bond and go to the oxygen
C) The curved arrow should start at the oxygen atom of the OH
D) There should be one more arrow
Ans: B
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
40. For the following reaction mechanism, identify the error, if any and describe the
modification necessary by drawing the correct mechanism.
+ Na NH2
H
Na
+ NH3
Ans: There is only one arrow and it is going in the wrong direction. The tail of the
curved arrow is placed on the hydrogen atom. The curved arrow represents
motion of electrons and not the motion of atoms. The curved arrow must start
from the base (high electron density) and should go to the proton on the acid (low
electron density)
+ Na NH2
H
Na
+ NH3
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Medium
41. For the following reaction mechanism, identify the error, if any and describe the
modification necessary by drawing the correct mechanism.
O
O
H
Br
+ NaBr
O Na
OH
Ans: The first arrow from the lone pair of oxygen atom is correct, but the second arrow
is incorrect. The tail of the arrow is placed on the proton. The second curved
arrow must start from the H—Br bond and should go to the bromine atom on the
acid.
O
O
H
Br
O Na
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Hard
+ NaBr
OH
42. Predict the products for the following acid-base reaction.
O
H
+ Na OH
Ans:
Na
O
+ H2O
Topic: Flow of Electron Density: Curved Arrow Notation
Section: 3.2
Difficulty Level: Hard
43. Predict the products for the following acid-base reaction.
Ans:
O
Na
+ NH3
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Easy
44. What is the Keq for the following reaction?
+ H3O
O
O
+ H2O
H
II.
I.
O
H3O
O
Keq=
H
Keq=
H2O
O
H3O
O
H
IV.
III.
Keq=
H
Keq=
H3O
O
A)
B)
C)
D)
E)
O
H2O
O
H
O
I
II
III
IV
Both II & III
Ans: C
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Easy
45. Which of the following compounds is most acidic?
O
O
O
OH
I
A)
B)
C)
D)
E)
II
NH2
O
III
I
II
III
IV
None of these
Ans: B
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Easy
IV
46. Which of the following compounds is most basic?
O
O
O
OH
I
A)
B)
C)
D)
E)
NH2
O
II
IV
III
I
II
III
IV
None of these
Ans: D
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Medium
47. Which of the following compounds is most acidic?
OH
OH
NH2
NH2
I
A)
B)
C)
D)
E)
II
III
I
II
III
IV
All of these
Ans: A
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Medium
IV
48. Which of the following compounds is most basic?
OH
OH
NH2
NH2
I
A)
B)
C)
D)
E)
II
III
IV
I
II
III
IV
All of these
Ans: C
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Medium
49. Which of the following compounds is most basic?
O
I
A)
B)
C)
D)
E)
II
III
I
II
III
IV
All of these
Ans: D
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Hard
IV
50. Tryptophan, an essential amino acid, is important in the synthesis of the
neurotransmitter serotonin in the body. It has the following structure. Circle the three
most acidic protons in tryptophan.
O
O
H
H
N
H
N
H
O
Ans:
O
H
H
N
H
N
H
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Hard
51. Histidine an amino acid has the following structure. Circle the three most acidic protons
in histidine.
H
H
H
O
N
C
C
H
CH 2
H
O
H
H
H
H
O
N
C
C
H
CH2
C
C
H
N
N
C
H
Ans:
H
H
O
H
C
C
N
N
H
C
H
H
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Medium
52. For the following acid-base reaction, predict which side the equilibrium is favored.
+ NaOH
O
+ H2O
O
H
A) favor right side
B) favor left side
C) neither
Ans: A
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Medium
53. For the following acid-base reaction, predict which side the equilibrium is favored.
OH
O
+ H2O
+ H3O
A) favor right side
B) favor left side
C) neither
Ans: B
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Hard
54. For the following acid-base reaction, predict which side the equilibrium is favored.
O
O
H
N
O
H
H
A) favor right side
B) favor left side
C) neither
Ans: A
Topic: Brønsted-Lowry Acid: Quantitative Perspective
Section: 3.3
Difficulty Level: Hard
O
N
H
H
55. For the following acid-base reaction, predict which side the equilibrium is favored.
O
O
Li
+
+
Li
A) favor right side
B) favor left side
C) neither
Ans: A
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
56.
A)
B)
C)
D)
Which of the following compounds is most acidic?
HF
HCl
HBr
HI
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
57.
A)
B)
C)
D)
Which of the following compounds is most acidic?
CH3OH
HCl
CH3SH
CH3NH2
Ans: B
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
58. Which of the following compounds is more acidic? Explain why.
HF and HBr
Ans: HBr is more acidic than HF. The Br- ion has larger atomic size than the F- ion,
which allows for spreading of charge over a larger volume of space. This results
in more stable anion and a weak conjugate base.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
59. Which of the following compounds is more acidic? Explain why.
CH3OH and CH3NH2
Ans: CH3OH is more acidic than CH3NH2. The conjugate base CH3O- is more stable
than CH3NH-, because oxygen is more electronegative than nitrogen and can
stabilize the negative charge better, resulting in weak conjugate base.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
60. Determine which proton is most acidic in the following compound. Explain why.
H
S
O
H
II
I
Ans: H(I) is more acidic as the sulfur atom in the conjugate base has larger atomic size
than the oxygen, which allows for spreading of charge over a larger volume of
space. This results in more stable anion and a weak conjugate base.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Hard
61. Rank the following protons in decreasing order (most to least) of acidity.
OH III
N
H
II
I H
A)
B)
C)
D)
E)
II>III>I
I>II>III
III>I>II
III>II>I
None of these
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
62. Which of the following compounds is most acidic?
O
O
O
OH
OH
I
A)
B)
C)
D)
II
O
IV
III
I
II
III
IV
Ans: A
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
63. Which of the indicated protons is most acidic?
H
H
I
A)
B)
C)
D)
H II
III
O
H
IV
I
II
III
IV
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
64. Rank the indicated protons in decreasing order (most to least) of acidity.
IH
O
II H
III H
A)
B)
C)
D)
E)
II>I>III
II>III>I
I>III>II
I>II>III
III>II>I
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
65. Which compound has the most acidic proton? Explain your choice.
O
H I
II
H
Ans: Compound II.
The conjugate base of both compounds is resonance stabilized. For compound II
the negative charge ends up on more electronegative oxygen atom in one of the
resonance structure whereas in compound I the negative charge is on less
electronegative carbon atom in every resonance structure.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Hard
66. Which of the indicated protons is most acidic? Explain your choice.
IH
O
II H
III H
Ans: H-I is most acidic because the conjugate base is resonance stabilized. The
negative charge is delocalized over four atoms, one oxygen atom and three carbon
atoms.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
67. Which of the following compounds is most acidic?
O
O
OH
I
A)
B)
C)
D)
I
II
III
IV
Ans: B
O
OH
F
II
O
OH
I
III
OH
Br
IV
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
68. Which of the following compounds is most acidic?
O
O
O
O
F
OH
F
A)
B)
C)
D)
OH
OH
I
Cl
II
OH
III
Br
IV
I
II
III
IV
Ans: A
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Easy
69. Which of the following compounds is most acidic?
O
F
OH
I
A)
B)
C)
D)
O
O
OH
F
Cl
II
I
II
III
IV
Ans: B
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
O
OH
III
OH
Br
IV
70. Which of the following compounds is most acidic?
O
Cl
F
OH
F
OH
OH
Cl
OH
II
I
A)
B)
C)
D)
O
O
O
Cl
IV
F
III
I
II
III
IV
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Hard
71. Rank the following compounds in decreasing order (most to least) of acidity.
O
Br
Br
OH
Br
A)
B)
C)
D)
E)
OH
OH
II
I
Br
Br
III>II>IV>I
II>IV>III>II
IV>III>II>I
IV>II>III>I
III>IV>II>I
Ans: E
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
72. Which of the indicated protons is most acidic?
II H
I H
S
O
H
O
IV
O
H III
A)
B)
C)
D)
E)
O
O
O
I
II
III
IV
All of these
Ans: D
Topic: Brønsted-Lowry Acid: Qualitative Perspective
III
Br
OH
Br
IV
Section: 3.4
Difficulty Level: Medium
73. Which of the indicated protons is most acidic? Explain why.
H I
H
CF3
N
II H
N
H
Ans: H-II is more acidic.
The conjugate base is stabilized by the inductive effect of the adjacent fluorine
atoms, which are closer to position II than position I.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
74. Explain why phenol is more acidic than ethanol.
O
H
H
O
ethanol
Phenol
Ans: The conjugate base of phenol is resonance stabilized, resulting in a weaker
conjugate base. The conjugate base of ethanol has localized charge.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Medium
75. Which of the following compounds is more acidic? Explain why.
O
H
N
H
I
II
Ans: Compound I is more acidic. The conjugate base of both compounds is resonance
stabilized. The conjugate base of I has negative charge on more electronegative
oxygen atom, resulting in a more stable conjugate base.
Topic: Brønsted-Lowry Acid: Qualitative Perspective
Section: 3.4
Difficulty Level: Hard
76. Aspartic acid, an amino acid, has the following structure. Circle the most acidic proton
in aspartic acid. Explain your choice.
H
O
O
O
H
H
N
H
O
H
Ans:
H
O
O
O
H
H
N
H
O
H
The conjugate base is stabilized by the inductive effect of the adjacent nitrogen
atom.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
77. For the following acid-base reaction, predict which side the equilibrium is favored.
+
O
F3C
OH
OH
+
F3C
O
A) favor right side
B) favor left side
C) neither
Ans: A
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
78. For the following acid-base reaction, predict which side the equilibrium is favored.
C
N
N
+
H
C
N
N
+
A) favor right side
B) favor left side
C) neither
Ans: B
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
79. For the following acid-base reaction, predict which side the equilibrium is favored.
+
+
A) favor right side
B) favor left side
C) neither
Ans: A
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
80. For the following acid-base reaction, predict which side the equilibrium is favored.
OH
S
O
+
SH
+
A) favor right side
B) favor left side
C) neither
Ans: B
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
81. For the following acid-base reaction, predict which side the equilibrium is favored.
Explain why.
OH
S
+
O
SH
+
Ans: Favors the left side.
Sulfur is a larger atom and the negative charge is spread over a larger volume of
space. This results in more stable anion and a weaker base.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
82. For the following acid-base reaction, predict which side the equilibrium is favored.
Explain why.
+
+
Ans: Favors the right side.
Both the base and the conjugate base have negative charge on carbon atom. The
negative charge on conjugate base is stabilized via resonance, resulting in a more
stable base.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
83. For the following acid-base reaction, predict which side the equilibrium is favored.
Explain why.
O
+
F3C
OH
OH
+
F3C
O
Ans: Favors the right side.
Both the base and the conjugate base have negative charge on oxygen atom. The
negative charge on conjugate base is stabilized via inductive effect of the fluorine
on the adjacent carbon, resulting in a more stable base.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
84. Determine if H2O is a suitable reagent to protonate the following compound.
O
A) yes
B) no
Ans: B
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
85. Determine if H2O is a suitable reagent to protonate the following compound.
O
H
O
S
O
O
A) yes
B) no
Ans: B
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
86. Determine if H2O is a suitable reagent to protonate the following compound. Explain
why.
N
H
Ans: Yes.
The conjugate base of water has negative charge on more electronegative oxygen
atom, making it more stable.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
87. Determine if H2O is a suitable reagent to protonate the following compound. Explain
why.
O
Ans: No.
The base and the conjugate base have localized negative charge on the oxygen
atom. This results in similar stability.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
88. Determine if NaOH is a suitable reagent to deprotonate the following compound.
A) Yes
B) No
Ans: B
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Easy
89. Determine if NaNH2 is a suitable reagent to deprotonate the following compound.
O
O
H
A) Yes
B) No
Ans: A
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
90. Determine if NaOH is a suitable reagent to deprotonate the following compound.
Explain why.
Ans: No.
The base has negative charge on more electronegative oxygen, whereas the
conjugate base has negative charge on less electronegative carbon atom.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Medium
91. Determine if NaNH2 is a suitable reagent to deprotonate the following compound.
Explain why.
O
O
H
Ans: Yes.
The conjugate base is resonance stabilized with delocalization of charge over two
oxygen atoms. This is more stable than the amide base, which has a negative
charge localized on one nitrogen atom.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Hard
92. Determine if CH3CH2ONa is a suitable reagent to deprotonate the following compound.
Explain why. Draw the complete reaction, including the curved arrow mechanism.
N
H
Ans: No.
+
N
+
N
Na
O Na
H
OH
The base has negative charge on more electronegative oxygen atom, compared to
a nitrogen atom in the conjugate base. This results in a more stable base.
Topic: Position of Equilibrium and Choice of Reagents
Section: 3.5
Difficulty Level: Hard
93. Determine if H2O is a suitable reagent to protonate the following compound. Explain
why. Draw the complete reaction, including the curved arrow mechanism.
S Na
Ans: No.
S
S Na
H
H
O
H
+ NaOH
Sulfur is a larger atom compared to an oxygen atom and the negative charge is
spread over a larger volume of space. Furthermore the sulfur anion is resonance
stabilized. These two factors results in more stable anion and a weaker base
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Easy
94.
A)
B)
C)
D)
Which of the following solvents can be used with NaNH2?
CH3CH2OH
CH3OH
H2O
Liquid NH3
Ans: D
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Easy
95.
A)
B)
C)
D)
E)
Which of the following solvents can not be used with (CH3)3COK?
(CH3CH2)2O
(CH3)3COH
H2O
Liquid NH3
None of these
Ans: C
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Easy
96.
A)
B)
C)
D)
E)
Which of the following solvents can be used with (CH3)3CLi?
CH3CH2OH
CH3OH
H2O
Liquid NH3
CH3(CH2)4CH3
Ans: E
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Easy
97. As a result of the "leveling effect," the strongest acid that can exist in appreciable
concentration in aqueous solution is ____.
A) H2SO4
B) HCl
C) H3O+
D) HNO3
E) All of these
Ans: C
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Medium
98. What is the leveling effect?
Ans: It is the deprotonation of a solvent by a base or protonation of solvent by an acid.
Topic: Leveling Effect
Section: 3.6
Difficulty Level: Medium
99. What is the strongest base that can be used with water as a solvent?
Ans: hydroxide
Topic: Counterions
Section: 3.8
Difficulty Level: Easy
100.
A)
B)
C)
D)
What is a cation?
a negatively charged ion
a positively charged ion
a sodium atom
Both B & C
Ans: B
Topic: Counterions
Section: 3.8
Difficulty Level: Easy
101.
A)
B)
C)
D)
What is the counterion in NaOCH2CH3?
Na+
NaO—
CH3CH2—
CH3CH2O—
Ans: A
Topic: Counterions
Section: 3.8
Difficulty Level: Easy
102.
A)
B)
C)
D)
What is the counterion in (CH3)3CLi?
CH3+
CH3—
C(CH3)3—
Li+
Ans: D
Topic: Counterions
Section: 3.8
Difficulty Level: Easy
103. What is a counterion in (CH3)3COK?
Ans: K+
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
104.
A)
B)
C)
D)
A Lewis acid is defined as _____.
a proton donor
an electron pair donor
a hydroxide donor
an electron pair acceptor
Ans: D
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
105.
A)
B)
C)
D)
A Lewis base is defined as _____.
a proton donor
an electron pair donor
a hydroxide donor
an electron pair acceptor
Ans: B
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
106.
A)
B)
C)
D)
E)
CH3CH2OCH2CH3, is best classified as a ____.
Brønsted-Lowry acid
Lewis acid
Brønsted-Lowry base
Lewis base
Both C & D
Ans: E
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
107.
A)
B)
C)
D)
E)
BF3, is best classified as a ____.
Brønsted-Lowry acid
Lewis acid
Brønsted-Lowry base
Lewis base
Both A & D
Ans: B
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
108. The following compound is best classified as a ____.
S
A)
B)
C)
D)
E)
Brønsted-Lowry acid
Lewis acid
Brønsted-Lowry base
Lewis base
Both C & D
Ans: E
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
109. The following compound is best classified as a ____.
A)
B)
C)
D)
E)
Brønsted-Lowry acid
Lewis acid
Brønsted-Lowry base
Lewis base
Both C & D
Ans: B
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
110.
A)
B)
C)
D)
E)
Which of the following compounds is not a Lewis acid?
BH3
AlCl3
CH3CH3
CH3CH2+
Both C & D
Ans: C
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
111.
A)
B)
C)
D)
E)
Which of the following compounds is not a Lewis acid?
BF3
FeCl3
CH3CH2+
Ph3P
none of these
Ans: D
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
112. For the following reaction, identify the Lewis acid.
Cl
Cl
+
Fe
Cl
Cl
Cl
I
A)
B)
C)
D)
Cl
Cl
Fe
Cl
II
Cl
Cl
III
I
II
III
Both I & III
Ans: A
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
113. For the following reaction, identify the Lewis acid.
H
H
H
B
H
N
+
NH2
H
H
I
B
II
H
A)
B)
C)
D)
I
II
III
Both I & III
Ans: A
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
H
III
114. For the following reaction, identify the Lewis acid.
A)
B)
C)
D)
E)
I
II
III
IV
None of these
Ans: A
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
115. For the following reaction, identify the Lewis acid.
O
N
+ O
N
II
I
A)
B)
C)
D)
O
O
III
I
II
III
None of these
Ans: B
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Easy
116. For the following reaction, identify the Lewis base.
H
H
H
B
H
N
+
NH2
H
H
I
B
II
H
A)
B)
C)
D)
I
II
III
None of these
Ans: B
Topic: Lewis Acids and Bases
H
III
Section: 3.9
Difficulty Level: Easy
117. For the following reaction, identify the Lewis base.
Cl
Cl
+
Fe
Cl
Cl
Cl
I
A)
B)
C)
D)
Cl
Cl
Fe
Cl
II
Cl
Cl
III
I
II
III
None of these
Ans: B
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
118. For the following reaction, identify the Lewis acid and the Lewis base.
AlCl3
+ AlCl3
Cl
Cl
Ans:
AlCl3
+ AlCl3
Cl
Cl
Lewis acid
Lewis base
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Medium
119. For the following reaction, identify the Lewis acid and the Lewis base.
H
H
N
+
NH2
Ans:
H
H
N
+
Lewis acid
NH2
Lewis base
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Hard
120. For the following reaction, identify the Lewis acid and the Lewis base and draw the
curved arrow mechanism.
Cl
Cl
+
Fe
Cl
Cl
Cl
Cl
Fe
Cl
Ans:
Cl
Cl
Cl
Cl
Cl
+
Fe
Cl
Cl
Cl
Cl
Fe
Cl
Cl
Cl
Cl
Lewis acid
Lewis base
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Hard
121. For the following reaction, identify the Lewis acid and the Lewis base and draw the
curved arrow mechanism.
H
H
N
+
NH2
Ans:
H
H
N
+
Lewis acid
NH2
Lewis base
Topic: Lewis Acids and Bases
Section: 3.9
Difficulty Level: Hard
122. Predict the product(s) for the following reaction and draw the curved arrow mechanism.
S
+ BF3
Ans:
BF3
S
+ BF3
Topic: Lewis Acids and Bases
S
Section: 3.9
Difficulty Level: Hard
123. Predict the product(s) for the following reaction and draw the curved arrow mechanism.
O
+ AlCl3
Ans:
O
O
O
AlCl3
AlCl3
+ AlCl3
Topic: Integrated Problems
Section: 3.1-3.5
Difficulty Level: Hard
124. For the following reaction identify the acid and the base and predict the products. Draw
the curved arrow mechanism for the formation of products and predict the direction of
the equilibrium.
H
N
+ Na CN
H
H
H
Ans:
N
N
+ Na CN
H
H
+ HCN + Na
H
H
Base
Acid
Topic: Integrated Problems
Section: 3.1-3.5
Difficulty Level: Hard
125. For the following reaction identify the acid and the base and predict the products. Draw
the curved arrow mechanism for the formation of products and predict the direction of
the equilibrium.
O
O
+
O
H
Ans:
O
O
O
+
O
H
Base
Acid
O
+
O
Topic: Integrated Problems
Section: 3.1-3.5
Difficulty Level: Hard
126. For the following reaction identify the acid and the base and predict the products. Draw
the curved arrow mechanism for the formation of products and predict the direction of
the equilibrium.
O
H
H
N
N
O
Ans:
N
+
H
H
H
O
H
H
N
N
O
N
+
H
Base
Acid
O
H
H
N
O
H
H
N
H
H
+
N
H