Chapter 5: Stereochemistry
1. What is the main carbohydrate in the seeds and roots of plants?
A) Starch B) Glucose C) Cellulose D) Glycogen
A)
B)
C)
D)
2. Which of the following statements about starch and cellulose is true?
Starch and cellulose are not stereoisomers.
In cellulose, the O atom joins two rings using one equatorial and one axial bond.
In starch, the O atom joins two rings using two equatorial bonds.
In cellulose, the O atom joins two rings using two equatorial bonds.
A)
B)
C)
D)
3. Which of the following statements about constitutional isomers if not true?
They have different IUPAC names.
They always have the same functional groups.
They have different physical properties.
They have different chemical properties.
A)
B)
C)
D)
4. Which of the following statements about stereoisomers is not true?
Stereoisomers have identical IUPAC names except for a prefix like cis or trans.
Stereoisomers differ in configuration.
Stereoisomers always have the same functional groups.
Stereoisomers differ only in their structural formula.
5. What is the relationship between the following two compounds?
A)
B)
Stereoisomers
Constitutional isomers
C) Identical
D) Not isomers, different compounds
6. What is the relationship between the following two compounds?
A)
B)
Constitutional isomers
Identical
C) Stereoisomers
D) Not isomers, different compounds
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Chapter 5: Stereochemistry
7. What is the relationship between the following two compounds?
A)
B)
Constitutional isomers
Identical
C) Stereoisomers
D) Not isomers, different compounds
8. What is the relationship between the following two compounds?
A)
B)
A)
B)
C)
D)
A)
B)
C)
D)
Constitutional isomers
Stereoisomers
C) Identical
D) Not isomers, different compounds
9. Which of the following is the definition of chirality?
The existence of a molecule with a mirror image.
The existence of a molecule with a carbon atom that has four different substituents.
The existence of a molecule that is superimposable on its mirror image.
The existence of a molecule that is not superimposable on its mirror image.
10. Which of the following statements is not true?
A molecule that is superimposable on its mirror image is said to achiral.
A molecule that is not superimposable on its mirror image is said to be chiral.
A molecule that is superimposable on its mirror image is said to be chiral.
A carbon atom bonded to four different groups is a stereogenic center.
11. Which of the following statements is true?
A)
Enantiomers are mirror images that are not superimposable.
B)
A molecule that is superimposable on its mirror image is chiral.
C)
A chiral molecule usually contains a plane of symmetry.
D)
An achiral molecule does not contain a plane of symmetry.
12. Which of the following statements is true?
A)
Achiral molecules usually contain a plane of symmetry.
B)
With one tetrahedral stereogenic center, a molecule may or may not be chiral.
C)
With two or more stereogenic centers, a molecule is always chiral.
D)
Chiral molecules usually contain a plane of symmetry.
A)
B)
C)
D)
13. Which of the following is the correct definition for a pair of enantiomers?
A pair of stereoisomers that have a plane of symmetry.
A pair of stereoisomers that are not mirror images of each other.
A pair of stereoisomers that are not superimposable mirror images of each other.
A pair of stereoisomers that are superimposable mirror images of each other.
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Chapter 5: Stereochemistry
14. Which of the following molecules has a plane of symmetry?
A) I B) II C) III D) IV
A)
B)
C)
D)
15. Which of the following statements is true?
The presence of a plane of symmetry makes a molecule chiral.
An achiral molecule must have one or more stereogenic centers.
All molecules that have stereogenic centers are chiral.
Stereoisomers that are not superimposable on their mirror image are enantiomers.
16. Which of the following molecules are chiral?
I. cis-1,3-Dibromocyclohexane
II. 1-Bromo-1-methylcyclohexane
III. trans-1-Bromo-3-methylcyclohexane
IV. cis-1-Bromo-3-methylcyclohexane
A) I, II B) II, III C) I, IV D) III, IV
17. Which of the following molecules are chiral?
I. 2-Chlorobutane
II. 3-Bromopentane
III. 1-Bromo-2-methylpropene
IV. 2-Bromo-3-methylbutane
A) I, II B) I, IV C) II, III D) III, IV
18. Which of the following molecules are achiral?
A) II, III
B) I, II C) I, IV
D) III, IV
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Chapter 5: Stereochemistry
19. Which of the following molecules are chiral?
A) II, III
B) I, II C) I, IV
D) III, IV
20. How many stereogenic centers are present in ephedrine, a bronchodilator and
decongestant?
A) 0
B) 1 C) 2
D) 3
21. How many stereogenic centers are present in the following compound?
A) 0
B) 1 C) 2
D) 3
22. How many stereogenic centers are present in fructose, a simple sugar?
A) 1
B) 2 C) 3
D) 4
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Chapter 5: Stereochemistry
23. How many stereogenic centers are present in the following compound?
A) 1
B) 2
C) 3 D) 4
24. How many stereogenic centers are present in menthol?
A) 1
B) 2 C) 3
D) 4
25. How many stereogenic centers are present in the following compound?
A) 1
B) 2
C) 3 D) 4
26. How many stereogenic centers are present in the following molecule?
A) 1
B) 2
C) 4 D) 5
27. How many stereoisomers are possible for a molecule with formula
CH3CHBrCH(OH)CH3?
A) 1 B) 2 C) 3 D) 4
28. How many stereoisomers can be drawn for a molecule with formula
CH3CH(OH)CH(OH)CH3?
A) 1 B) 2 C) 3 D) 4
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Chapter 5: Stereochemistry
29. What is the total number of possible stereoisomers for the following molecule?
A) 2
B) 4 C) 6
D) 8
30. How many isomers can be drawn (constitutional and stereoisomers) for
dimethycyclopropane?
A) 2 B) 3 C) 4 D) 6
31. How many chiral stereoisomers can be drawn for dimethycyclopropane?
A) 1 B) 2 C) 3 D) 4
32. How many stereogenic centers are present in gabapentin, used clinically to treat seizures
and certain types of chronic pain?
A) 0
B) 1 C) 2 D) 3
33. How many stereogenic centers are present in the following compound?
A) 0
B) 1
C) 2 D) 3
34. Rank the following groups in order of decreasing priority according to the Cahn-IngoldPrelog system.
A)
B)
III > I > II > IV
I > II > IV > III
C) III > II > IV > I
D) III > IV > II > I
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Chapter 5: Stereochemistry
35. Rank the following groups in order of decreasing priority according to the Cahn-IngoldPrelog system.
A)
B)
I > II > III > IV
II > I > IV > III
C) II > I > III > IV
D) I > II > IV > III
36. Rank the following groups in order of decreasing priority according to the Cahn-IngoldPrelog system.
A)
B)
I > III > IV > II
III > IV > I > II
C) IV > III > I > II
D) IV > I > III > II
37. Rank the following groups in order of decreasing priority according to the Cahn-IngoldPrelog system.
A)
B)
I > II > IV > III
IV > II > I > III
C) IV > I > II > III
D) III > II > I> IV
38. Rank the following groups in order of decreasing priority according to the Cahn-IngoldPrelog system.
A)
B)
IV > III > I > II
IV > I > III > II
C) III > IV > I > II
D) II > I > III > IV
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Chapter 5: Stereochemistry
39. Which of the following compounds has a plane of symmetry?
A) I and II B) II and III C) II, III and IV
D) III and IV
40. Which of the following structures has a different configuration from the other three?
A) I B) II C) III D) IV
41. Which of the following structures has a different configuration from the other three?
A) I B) II C) III
D) IV
42. Which of the following structures has the S configuration?
A) Only I B) Only II
C) Only I and II D) I, II and III
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Chapter 5: Stereochemistry
43. Which of the following structures has the R configuration?
A) Only I B) Only II C) Only I and II D) I, II and III
44. Which of the following structures has the R configuration?
A) Only I B) Only II
A)
B)
C)
D)
C) Only I and II D) I, II and III
45. Which of the following is the definition for a pair of diastereomers?
A pair of stereoisomers with stereogenic centers which is not chiral.
A pair of stereoisomers that are superimposable mirror images of each other.
A pair of stereoisomers that are not superimposable mirror images of each other.
A pair of stereoisomers that are not mirror images of each other.
46. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
47. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
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C) Enantiomers
D) Identical
Chapter 5: Stereochemistry
48. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
49. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
50. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
51. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
52. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
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C) Enantiomers
D) Identical
Chapter 5: Stereochemistry
53. What is the relationship between the following compounds?
A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Identical
54. Which of the following statements about meso compounds is not true?
A)
A meso compound generally has a plane of symmetry.
B)
A meso compound and its mirror image are identical.
C)
A meso compound is achiral.
D)
A meso compound is chiral.
A)
B)
55. Which of the following compounds is a meso compound?
(2R, 3S)-dichlorobutane
C) (2R, 3S)-3-chloro-2-butanol
(2R, 3R)-dichlorobutane
D) (2R, 3R)-3-chloro-2-butanol
56. Which of the following compounds are meso?
A) Only I B) Only II C) I and II D) Neither
57. Which of the following compounds can have a meso stereoisomer?
A) I B) II C) III
D) IV
58. How many stereoisomers of 1,3-dibromocyclopentane exist?
A) 1 B) 2 C) 3 D) 4
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Chapter 5: Stereochemistry
59. Which of the following compounds does not have a plane of symmetry?
A) Only I and II B) Only II C) Only III and IV D) Only I, II and IV
60. Which of the following cyclic molecules is a meso compound?
A) I B) II C) III D) IV
61. How many isomers (constitutional and stereoisomers) exist for dimethylcyclobutane?
A) 3 B) 4 C) 5 D) 6
62. A natural product was isolated in the laboratory, and its observed rotation was +10°
when measured in a 1 dm sample tube containing 1.0 g of compound in 10 mL of H2O.
What is the specific rotation of this compound?
A) -10° B) +100° C) +10° D) -100°
63. A solution containing 0.08 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates
plane polarized light by +4°. What is the specific rotation of the S enantiomer?
A) +50° B) -40° C) +40° D) -50°
64. How much of the R enantiomer is present in 10 g of a mixture which has an
enantiomeric excess of 30% of the S isomer?
A) 3.0 g B) 3.5 g C) 6.5 g D) 7.0 g
65. A solution containing 0.4 g/mL of a pure S enantiomer is a 1 dm polarimeter rotates
plane polarized light by +5.6°. What is the rotation of a solution containing 0.8 g/mL of
the S enantiomer in the same polarimeter.
A) +5.6° B) +11.2° C) +2.8° D) +1.4°
66. What is the percent ee of a mixture that has 70% of one enantiomer and 30% of the
other?
A) 70 B) 85 C) 40 D) 30
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Chapter 5: Stereochemistry
67. If a mixture has an ee of 90%, what is the percentage of each enantiomer?
A) 65% : 35% B) 55% : 45% C) 80% : 20% D) 95% : 5%
68. A reaction mixture is three parts of one enantiomer and one part of the other. What is
the percent ee of this mixture?
A) 75 B) 40 C) 65 D) 50
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Chapter 5: Stereochemistry
Answer Key
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Chapter 5: Stereochemistry
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