Organic Chemistry, 8e (Bruice) Module 8 Practice Test 1 Copyright © 2017 Pearson Education, Inc. Chapter 20 The Organic Chemistry of Carbohydrates 1. Which of the following represents the general...

Organic Chemistry, 8e (Bruice)
Module 8 Practice Test
1
Copyright © 2017 Pearson Education, Inc.
Chapter 20 The Organic Chemistry of Carbohydrates
1. Which of the following represents the general formula of a carbohydrate? Section: 20-0
A) CnH2n+2 B) CnH2n C) CnH2n-2 D) Cn(H2O)n E) Cn(HO)n
2. Which of the following best represents the process of photosynthesis? Section: 20-0
A) disproportionation XXXXXXXXXXB) oxidation/reduction C) exothermic D) exergonic E) elimination
3. A carbohydrate composed of three to ten sugar molecules is called a(n)
A) single carbohydrate. B) disaccharide. C) oligosaccharide.
D) polysaccharide. E) monosaccharide XXXXXXXXXXSection: 20-1
4. Which of the following compounds is a D-sugar? Section: 20-2
A) XXXXXXXXXXB XXXXXXXXXXC XXXXXXXXXXD) E)


5. All chiral D-sugars rotate plane-polarized light XXXXXXXXXXSection: 20-2
A) clockwise. B) counterclockwise. C) +20.0°.
D) in a direction that cannot be predicted but must be determined experimentally.
E) since they are optically inactive.
6. Is the following structure of glucose a D or L configuration? Explain. Section: 20-2


7. Epimers are essentially XXXXXXXXXXSection: 20-3
A) enantiomers. B) diasteromers. C) identical. D) constitutional isomes. E) tautomers.
8. Which of the following corresponds to the definition of an aldopentose? Section: 20-3
I. It is a monosaccharide. II. It contains a CHO group
III. It is a disaccharide. IV. It is an oligosaccharide.
A) I and II B) II and III C) I and IV D) I and III E) I, II, and III
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9. Is L-glucose the enantiomer of D-glucose, the C-5 epimer of D-glucose, or both? Section: 20-3

10. What is the relationship between the following compounds? Section: 20-3

A) conformational isomers B) constitutional isomers C) identical
D) enantiomers E) diastereomers
11. At which carbon are the following sugars epimers of each other? Section: 20-3

A) C-1 B) C-2 C) C-3 D) C-4 E) C-5
12. At which carbon are the following sugars epimers of each other? Section: 20-3

A) C-1 B) C-2 C) C-3 D) C-4 E) C-5
13. How many chirality centers are there in an aldohexose? Section: 20-3
A) 2 B) 3 C) 4 D) 5 E) 6
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14. Assign the proper configurational descriptor to each asymmetric center (R or S) in D-glucose below.
XXXXXXXXXXSection: 20-3
15. The open-chain form of D-idose is shown below. Draw the open-chain form of the C-3 epimer of D-idose.
XXXXXXXXXXSection: 20-3
16. Fructose is described as a(n XXXXXXXXXXSection: 20-4
A) aldopentose. B) ketopentose. C) aldohexose. D) ketohexose. E) none of the above.
17. At which carbon are the following sugars epimers of each other? Section: 20-4

A) C-1 B) C-2 C) C-3 D) C-4 E) C-5
18. How many chirality centers are there in a 2-ketohexose? Section: 20-4
A) 2 B) 3 C) 4 D) 5 E) 6
19. How many stereoisomers are possible for a 2-ketohexose? Section: 20-4
A) 2 B) 4 C) 8 D) 16 E) 32
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20. Draw the enolate of D-glucose XXXXXXXXXXSection: 20-5


21. What is epimerization? XXXXXXXXXXSection: 20-5
A) involves changing the configuration of a carbon of a monosaccharide through deprotonation followed by
reprotonation
B) involves oxidation of an aldose C) involves lengthening the chain of an aldose
D) involves reduction of an aldose E) none of the above
22. When D-threose is treated with NaBH XXXXXXXXXXSection: 20-6
A) a 70:30 mixture of enantiomeric alditols results.
B) a 50:50 mixture of enantiomeric alditols results.
C) a meso alditol is produced.
D) the product mixture contains two diastereomeric alditols.
E) an optically active alditol is produced.
23. Which of the following sugars yields the same alditol upon reduction with NaBH4 as does D-glucose?
Section: 20-6
A) D-fructose B) D-mannose C) L-glucose D) D-arabinose E) none of the above
24. Reduction of a 2-ketohexose with NaBH4 yields Section: 20-6
A) a single aldohexose. B) a mixture of acetals. C) a mixture of alditols.
D) a mixture of cyclic hemiacetals. E) a single pyranose.
25. Which of the following is/are the product(s) obtained from the reduction of D-fructose? Section: 20-6
XXXXXXXXXXA) XXXXXXXXXXB) C)

D) A and B E) A and C
26. Provide the Fischer projection of the open-chain form of the aldonic acid which results when L-glucose is
treated with bromine water XXXXXXXXXXSection: 20-6
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27. Which of the following monosaccharides will form D-glucaric acid (shown below) upon oxidation with
nitric acid?
XXXXXXXXXXSection: 20-6
XXXXXXXXXXA) XXXXXXXXXXB) XXXXXXXXXXC)


D) A and B E) A and C
28. When D-sorbose (shown below) is treated with NaBH4, which of the following is produced? Section: 20-6

A) a single optically active alditol B) a single optically inactive alditol
C) a racemic mixture of alditols D) an optically inactive mixture of epimeric alditols
E) an optically active mixture of epimeric alditols
29. Provide the structure of the product which results when D-ribose is treated with bromine water.
Section: 20-6
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30. When D-tagatose is added to a basic aqueous solution, an equilibrium mixture of three monosaccharides is
obtained. Identify the monosaccharides.
XXXXXXXXXXSection: 20-6
31. Provide the major organic product(s) of the reaction below. Section: 20-6
A)

B)

32. Give the major product(s) for the reaction. You may choose more than one answer. Section: 20-6
A) XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)
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33. Give the major product(s) for the reaction XXXXXXXXXXSection: 20-6

A) XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)
34. Give the major product(s) for the following reaction XXXXXXXXXXSection: 20-6

A) no reaction XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)


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35. Give the major product(s) for the following reaction XXXXXXXXXXSection: 20-6

A) no reaction XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)


36. Give the major product(s) for the following reaction XXXXXXXXXXSection: 20-6

A) no reaction XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)
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37. Give the major product(s) for the following reaction XXXXXXXXXXSection: 20-6

A) no reaction XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)


38. Give the major product(s) for the following reaction XXXXXXXXXXSection: 20-6

A) no reaction XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)


39. Which of the following sequences is known as a Kiliani-Fischer chain elongation? Section: 20-7
A) 1. Fe3+, H2O2 2. Br2, H2O 3. Ca(OH)2 B) 1. CN- 2. H2, Pd/BaSO4 3. H3O+
C) 1. NaBH4 2. H2O 3. Br2, H2O
D) 1. acetic anhydride (excess), pyridine 2. CH3I (excess), Ag2O
E) 1. CH3OH, H+, Δ 2. AgNO3, Δ
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40. Which monosaccharides are formed in the Kiliani-Fischer synthesis starting with D-xylose?

A) D-glucose and D-mannose B) D-glucose and D-idose
C) D-galactose and D-talose D) D-allose and D-altrose
E) D-ribose and D-arabinose XXXXXXXXXXSection: 20-7
41. Provide the open-chair structures of the two monosaccharides that result when D-threose undergoes the
Kiliani-Fischer synthesis XXXXXXXXXXSection: 20-7
42. What nucleophilic carbon species is used in the Kiliani-Fischer synthesis? Section: 20-7

43. Give the product(s) for each step of the following reaction. Section: 20-7


44. Give the product(s) for each step of the following reaction. Section: 20-8


45. An aqueous solution of glucose behaves as an aldehyde because Section: 20-10
A) it is hydrolyzed by water to the free aldehyde.
B) it is a ketone, but is in equilibrium with the aldehyde form.
C) glucose is actually a cyclic aldehyde.
D) its cyclic hemiacetal, the predominant form, is in equilibrium with the free aldehyde form.
E) it can be oxidized with periodic acid.
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46. Give the major product(s) for the following reaction. Section: 20-8
A) XXXXXXXXXXB) XXXXXXXXXXC) XXXXXXXXXXD) XXXXXXXXXXE)


47. Which of the following is the cyclic hemiacetal formed from 4-hydroxyheptanal? Section: 20-10


48. Which of the following statements best describes the meaning of mutorotation? Section: 20-10
A) a rapid exchange between the α and β forms of diasternomeric sugars
B) a rapid exchange between the D and L forms
C) a slow exchange between hydrogen and deuterated hydrogen
D) a slow change in optical rotation to reach an equilibrium value
E) a slow change in absolute configuration to reach an equilibrium value
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49. Which of the following is the Haworth projection of β-D-galactopyranose? Section: 20-10


50. Which of the following is the Haworth projection of a α-D-tagatofuranose? Section: 20-10


51. In solution, glucose exists as XXXXXXXXXXSection: 20-10
A) the open-chain form only. B) the cyclic hemiacetal form only.
C) the cyclic acetal form only.
D) an equilibrium mixture of the open-chain form and cyclic acetal forms.
E) an equilibrium mixture of the open-chain form and cyclic hemiacetal forms.
52. When a monosaccharide reacts to give the pyranose form from its open-chain form, how many distinct
pyranose forms are possible? XXXXXXXXXXSection: 20-10
A) 1 B) 2 C) 4 D) 2n, where n is the number of carbons present
E) 4n + 2, where n is the number of carbons present
53. Six-membered cyclic hemiacetals and five-membered cyclic hemiacetals are called, respectively
A) mannoses and xyloses. B) maltoses and arabinoses. C) pyranoses and fructoses.
D) glycoses and fructoses. E) none of the above. Section: 20-10
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54. Anomers of D-glucopyranose differ in their stereochemistry at Section: 20-10
A) C1. B) C2. C) C3. D) C4. E) C5.
55. A pyranose with the hydroxyl group on the anomeric carbon pointing up in the Haworth structure is
designated
A) a'. B) b'. C) α. D) β. E) f. Section: 20-10
56. When pure α-D-glucopyranose is dissolved in water, the optical rotation of the resulting solution changes
over a period of time. What is the name of this phenomenon and why does it occur? Section: 20-10
57. Draw the Haworth structure of
A) α-D-ribofuranose. B) β-D-glucopyranose Section: 20-10
58. Draw the more stable chair conformer of α-D-glucopyranose. Section: 20-11

59. Given the structure of D-altrose below, provide the Haworth structure of β-D-altropyranose. Section: 20-10


60. Given the structure of D-talose below, provide the Haworth structure of α-D-talopyranose. Section: 20-10


61. Give the name for the following structure XXXXXXXXXXSection: 20-10


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62. The open-chain form of D-idose is shown below. Draw the Haworth projection of a-D-idopyranose.
XXXXXXXXXXSection: 20-10
63. The open-chain form of D-idose is shown below. Draw the Haworth projection of b-D-idopyranose.
XXXXXXXXXXSection: 20-10
64. Provide the Haworth projection of ethyl-β-D-mannopyranoside. Section: 20-10

65. Which of the following statements regarding methyl-β-L-glucopyranoside is correct? Section: 20-10
A) This glycoside is a reducing sugar.
B) This glycoside undergoes mutorotation in aqueous base.
C) This glycoside will undergo no reaction when treated with excess CH3I/Ag2O.
D) This glycoside will be hydrolyzed to the cyclic hemiacetal in dilute aqueous acid.
E) This glycoside will readily undergo Kiliani-Fischer chain elongation.
66. Why is β-D-glucopyranose more stable in nature than α-D-glucopyranose? Section: 20-11

67. Given the structure of D-arabinose below, provide the structure of the glycoside methyl α-D-
arabinofuranoside.
XXXXXXXXXXSection: 20-12
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68. Which of the following statements best describes the meaning of a glycoside? Section: 20-12
A) It is the mirror image of a sugar. B) It is the hemiacetal of a sugar.
C) It is the acetal of a sugar. D) It is the enantiomer of a sugar.
E) It is the enol-keto form of a sugar.
69. Which of the following is methyl-α-D-glucopyranoside? Section: 20-12


70. Which of the following represents a glycosidic bond? Section: 20-12


71. Provide the major organic product(s) of the reaction shown. Section: 20-12
A)

B)

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72. Give the major product(s) for the following reaction. You may choose more than one answer.
A) XXXXXXXXXXB) XXXXXXXXXXC)


XXXXXXXXXXD) XXXXXXXXXXE)
XXXXXXXXXXSection: 20-12
73. Which of the following compounds is a nonreducing sugar? Section: 20-14

74. Which of the following would give a positive Tollen's test? Section: 20-14
A) α-D-glucopyranose B) methyl β-D-glucopyranoside C) sucrose
D) methyl α-D-ribofuranoside E) none of the above
75. Which of the following is true about sucrose? Section: 20-15
A) It hydrolyzes to fructose and glucose. B) It is a reducing sugar.
C) It is a monosaccharide. D) It undergoes mutorotation in water.
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