Radical Reactions Chapter 10 4th Edition Verified Test Bank

Organic Chemistry, 4e (Klein)

Chapter 10 Radical Reactions

1) Which choice shows the product(s) of the homolytic cleavage of the C-C bond of ethane?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

2) Which of the following radicals is the most stable?

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

3) In the molecule shown, which of the highlighted C-H bonds (labeled from a to e) is expected to have the lowest bond dissociation energy.

A) C-Ha

B) C-Hb

C) C-Hc

D) C-Hd

E) C-He

Diff: 1

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

4) Use the appropriate type of arrows to show the movement of electrons during the homolytic bond cleavage of ethane.

A) I

B) II

C) III

D) IV

E) V

Diff: 2

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

5) Rank the following radicals in order of decreasing stability (i.e., from most stable to least stable).

A) IV > I > II > III

B) III > I > II > IV

C) III > II > I > IV

D) III > IV > II > I

E) II > III > I > IV

Diff: 3

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

6) Rank the following radicals in order of decreasing stability (i.e., from most stable to least stable).

A) IV > I > II > III

B) III > I > II > IV

C) III > II > I > IV

D) III > IV > II > I

E) II > I > III > IV

Diff: 2

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

7) Which structure is a valid resonance structure of the radical shown?

A) I

B) II

C) III

D) IV

E) V

Diff: 2

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

8) Which resonance structures below represents the most reasonable resonance structure for the radical shown?

A) I

B) II

C) III

D) IV

E) V

Diff: 2

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

9) For the following structure, which of the indicated C-H bonds is the weakest?

A) C-Ha

B) C-Hb

C) C-Hc

D) C-Hd

E) C-He

Diff: 1

Learning Objective: 10.1 Compare the order of stability of primary, secondary, tertiary radicals with that of carbocations, and also discuss the stability of allylic and benzylic radicals

10) Which term most accurately describes the process shown?

A) coupling

B) proton transfer

C) halogen abstraction

D) hydrogen abstraction

E) homolytic cleavage

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

11) Select the option that correctly shows the movement of electrons during the reaction shown.

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

12) Which term most accurately describes the process shown?

A) hydrogen abstraction

B) halogen abstraction

C) homolytic cleavage

D) coupling

E) elimination

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

13) Select the option that correctly shows the movement of electrons during the process shown.

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

14) Which term most accurately describes the process shown?

A) coupling

B) hydrogen abstraction

C) halogen abstraction

D) homolytic cleavage

E) addition to a π bond

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

15) Select the option that correctly shows the movement of electrons during the process shown.

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

16) Which term most accurately describes the process shown below?

A) coupling

B) elimination

C) halogen abstraction

D) hydrogen abstraction

E) homolytic cleavage

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

17) Select the option that correctly shows the movement of electrons during the process shown.

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

18) Which of the reactions shown represents an example of termination?

A) I

B) II

C) III

D) IV

E) none of the above

Diff: 1

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

19) Which of the reactions shown is an example of initiation?

A) I

B) II

C) III

D) IV

E) none of the above

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

20) Which of the choices is an example of a radical initiation step?

A) homolytic cleavage

B) heterolytic cleavage

C) hydrogen abstraction

D) coupling

E) hydrogen addition

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

21) Which of the choices is an example of a propagation step?

A) homolytic cleavage

B) heterolytic cleavage

C) hydrogen abstraction

D) coupling

E) homolytic bond formation

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

22) Identify an example of a termination step.

A) homolytic cleavage

B) heterolytic cleavage

C) hydrogen abstraction

D) coupling

E) hydrogen addition

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

23) Which option correctly shows the result of a feasible addition of a radical to a π bond?

A) I

B) II

C) III

D) IV

E) V

Diff: 2

Learning Objective: 10.2 Name six different kinds of reactions found in radical mechanisms and the three stages of these mechanisms

24) Which of the following represents a propagation step in the monochlorination of methylene chloride (CH2Cl2)?

A) I

B) II

C) III

D) IV

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

25) Which of these choices would you expect to function as an initiator at a lower temperature than the other choices?

A) I

B) II

C) III

D) IV

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

26) Select the option that correctly shows the movement of electrons during the a propagation step in the chlorination of propane?

A) I

B) II

C) III

D) IV

E) V

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

27) Which of the choices are possible termination steps in the chlorination of methane?

A) I and II

B) III and IV

C) I and III

D) II and IV

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

28) Which of the following compounds is most reactive toward chlorination?

A) methane

B) chloromethane

C) dichloromethane

D) chloroform

E) ethane

Diff: 1

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

29) What steps are needed to minimize the production of polyhalogenated products during the free radical chlorination of ethane?

A) use an excess of chlorine

B) use an excess of ethane

C) use equimolar chlorine and ethane

D) it is not possible to minimize the production of higher halogenated products

Diff: 1

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

30) Which of the following shows the initiation step of monochlorination of methane?

A) I

B) II

C) III

D) IV

E) I and II

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

31) How many constitutional isomers are possible if propane is dichlorinated?

A) 1

B) 2

C) 3

D) 4

E) 5

Diff: 2

Learning Objective: 10.3 Describe the stages in the radical chlorination of methane, and explain which stage that gives the net chemical reaction

32) Which of the following processes causes the free radical bromination of methane to be slower than the equivalent free radical chlorination?

A) initiation

B) hydrogen abstraction

C) halogen abstraction

D) termination

E) entropy

Diff: 1

Learning Objective: 10.4 Discuss which halogenation reactions are of practical use in the laboratory and explain why others are not

33) Which of the following is the rate-determining step in the free-radical bromination of methane?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.4 Discuss which halogenation reactions are of practical use in the laboratory and explain why others are not

34) Predict the major product obtained upon radical bromination of t-butylcyclohexane.

A) 1-bromo-1-tert-butylcyclohexane

B) 2-bromo-1-tert-butylcyclohexane

C) 3-bromo-1-tert-butylcyclohexane

D) 4-bromo-1-tert-butylcyclohexane

E) 1-bromo-1,1-dimethylethylcyclohexane

Diff: 2

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

35) Cyclic compound A has molecular formula C5H10 and undergoes monochlorination to yield exactly three different constitutional isomers. Which of the following shows compound A?

A) I

B) II

C) III

D) IV

E) V

Diff: 3

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

36) Predict the major product of the reaction shown.

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

37) Predict the major product(s) of the reaction shown.

A) I

B) II

C) III

D) IV

E) I and II

Diff: 1

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

38) Two compounds, A and B, each have molecular formula C6H14. Monochlorination of compound A results in the formation of two constitutional isomers. Monochlorination of compound B results in the formation of four constitutional isomers. Which choices below correctly identifies compounds A and B?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

39) Which of the following statements correctly describes the nature of the transition state of the rate-determining step of the free-radical bromination of methane?

A) the transition state resembles the reactants more than the products

B) the transition state resembles the products more than the reactants

C) the transition state equally resembles the products and reactants

D) the transition state resemblance to reactants vs products is temperature-dependent

Diff: 3

Learning Objective: 10.5 Describe the selectivity of halogenation reactions, and compare the positions of bromination and chlorination reactions on alkanes

40) Predict the major product(s) of the reaction shown.

A) I

B) II

C) I and III

D) II and III

E) I, II, and III

Diff: 1

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

41) What is the correct name for the major product of the reaction shown?

A) (R)-3-bromo-3-ethylbutane

B) (S)-3-bromo-3-ethylbutane

C) (R)-3-bromo-3-methylpentane

D) (S)-3-bromo-3-methylpentane

E) 3-bromo-3-methylpentane

Diff: 1

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

42) Predict the product(s) of the reaction shown.

A) I

B) II

C) III

D) I and III

E) III and IV

Diff: 1

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

43) Predict the major product(s) of the reaction shown.

A) I

B) II and IV

C) III and V

D) I and IV

E) V

Diff: 1

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

44) Predict the major product(s) of the following reaction.

A) I

B) I and II

C) I, II, and III

D) I, II, and IV

E) IV

Diff: 3

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

45) Compound A has molecular formula C9H20. Compound A produces exactly three constitutional isomers upon monochlorination and produces one major constitutional isomer upon monobromination. Which of the following are possible structures of compound A?

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

46) Which of the following are possible product(s) of the reaction shown?

A) I

B) I, II

C) I, II, IV, V

D) I, III, IV, V

E) I, II, III, IV, IV

Diff: 3

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

47) Explain whether the major product(s) of the following reaction is optically active and why this is the case.

A) The product is optically active because a chiral center is created at the right side vertex of the ring.

B) The product is optically active because it has a chiral center at a terminal carbon.

C) The product is not optically active because it has a chiral center that is part of the ring.

D) The product is not optically active because its chiral center is not part of the ring.

E) The product is not optically active because it has no chiral centers.

Diff: 2

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

48) Is the product of the reaction below optically active?

A) Yes, because the reaction produces an optically active product with a chiral center.

B) Yes, because the reaction produces an optically active product with a Br on a terminal carbon.

C) No, because the reaction produces a meso compound.

D) No, because the reaction produces a racemic mixture.

E) No, because it is impossible to predict where B r will be added.

Diff: 2

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

49) How many monochlorination products of 3,3-dimethylpentane are possible, including stereoisomers?

A) 1

B) 2

C) 4

D) 6

E) 8

Diff: 2

Learning Objective: 10.6 Describe the circumstances that produce racemic mixtures from radical halogenation reactions

50) Identify the expected major product(s) of the reaction shown.

A) I

B) II

C) III

D) I and III

E) I and IV

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

51) What reagent(s) would best accomplish the following synthesis?

A) Br2

B) PBr3

C) CH3Br

D) NBS, heat

Diff: 1

Learning Objective: 10.7 Describe the allylic bromination of alkenes

52) Which of the choices are major product(s) of the reaction shown?

A) I

B) I, II

C) I, IV

D) I, III

E) I, II, III, IV

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

53) Compound A has molecular formula C6H12. Upon treatment with NBS and irradiation with UV light, exactly two constitutional isomers are formed. Which of the following is a possible structure for compound A?

A) I

B) II

C) III

D) I and II

E) I and III

Diff: 3

Learning Objective: 10.7 Describe the allylic bromination of alkenes

54) Which of the structures shown are examples of the monobrominated compounds (including stereoisomers) produced when 2-propyl-1-pentene is treated with NBS and UV light irradiation?

A) (R)-3-bromo-3-propyl-1-pentene and (Z)-4-(bromomethyl)-3-heptene

B) (S)-3-bromo-2-propylpentane and (E)-4-(bromomethyl)-3-heptene

C) (S)-3-bromo-3-propylpentane and (Z)-4-(bromomethyl)-3-heptene

D) (R)-4-bromo-3-propyl-1-pentene and (Z)-4-(bromomethyl)-3-heptene

E) (Z)-4-bromomethyl)-2-heptene and (E)-1-bromo-2-propyl-2-pentene

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

55) Which of the structures shown are monobrominated compounds (including stereoisomers) produced when 1-ethyl-4-methylbenzene is treated with NBS and UV light irradiation?

A) I

B) II and III

C) I, II, and V

D) I, III, and V

E) I, IV, and V

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

56) Which are the two monobrominated compounds produced when 2-isopropyl-3-methyl-1-butene is treated with NBS and UV light irradiation?

A) I and II

B) II and III

C) I and III

D) I and IV

E) III and IV

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

57) How many monobrominated compounds are produced when 2-methyl-2-butene is treated with NBS and UV light irradiation?

A) 2

B) 4

C) 6

D) 8

E) 10

Diff: 2

Learning Objective: 10.7 Describe the allylic bromination of alkenes

58) Which of the following compounds would be expected to be least destructive to the ozone layer?

A) CCl3F

B) CCl2F2

C) CCl2FCCl2F

D) CF3CH2F

Diff: 1

Learning Objective: 11.8 Explain the role of ozone in the atmosphere and why it is important to life on earth's surface

59) Which of the following shows the correct products initially formed when ozone absorbs ultraviolet light?

A) I

B) II

C) III

D) IV

Diff: 2

Learning Objective: 11.8 Explain the role of ozone in the atmosphere and why it is important to life on earth's surface

60) Use arrows to show the second propagation step for the reaction of a chlorine radical with ozone.

Diff: 1

Learning Objective: 11.8 Explain the role of ozone in the atmosphere and why it is important to life on earth's surface

61) Which of the following is expected to be a major product for the reaction shown?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.9 Describe the conditions necessary for an autooxidation reaction, the products of such reactions, and the utility of antioxidants

62) Which of the following is expected to function as an antioxidant?

A) I

B) II

C) III

D) I and II

E) III and V

Diff: 1

Learning Objective: 10.9 Describe the conditions necessary for an autooxidation reaction, the products of such reactions, and the utility of antioxidants

63) Which term best describes the process shown?

A) neutralization

B) propagation

C) termination

D) initiation

E) elimination

Diff: 1

Learning Objective: 10.9 Describe the conditions necessary for an autooxidation reaction, the products of such reactions, and the utility of antioxidants

64) Which term best describes the process shown?

A) neutralization

B) propagation

C) termination

D) initiation

E) elimination

Diff: 1

Learning Objective: 10.9 Describe the conditions necessary for an autooxidation reaction, the products of such reactions, and the utility of antioxidants

65) Predict the major product(s) of the reaction shown.

A) I

B) II

C) III

D) IV

E) II and III

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

66) Identify the intermediate that leads to the major product in the reaction of 2-methyl-2-butene with hydrogen bromide and hydrogen peroxide.

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

67) What reagent(s) should be added to 2-methyl-2-butene to generate the intermediate shown?

A) hydrogen bromide and hydrogen peroxide

B) Br2 in the presence of ultraviolet light

C) Br2 in the presence of NBS

D) hydrogen bromide and ultraviolet light

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

68) Predict the product(s) of the reaction shown.

A) I

B) II

C) II, III

D) II, III, IV

E) I, II, III, IV

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

69) Of the four choices shown, which is likely to be a major product of the reaction shown?

A) I

B) II

C) III

D) IV

Diff: 3

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

70) Compound A reacts with HBr/ROOR to give compound B. Compound C reacts with bromine and light to produce the same compound (compound B). What are likely structures for compounds A, B, and C?

A) Compound A is I, Compound B is II, and Compound C is III

B) Compound A is II, Compound B is I, and Compound C is IV

C) Compound A is III, Compound B is II, and Compound C is IV

D) Compound A is I, Compound B is III, and Compound C is II

E) Compound A is II, Compound B is IV, and Compound C is III

Diff: 3

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

71) Which of the steps shown is thermodynamically unfavorable at all temperatures?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

72) Which choice shows the product of the reaction shown?

A) I

B) I or II

C) II

D) II or III

E) IV

Diff: 1

Learning Objective: 10.10 Describe the mechanism and regiochemistry of the radical reaction of HBr with alkenes

73) Determine the repeat unit for the polymer produced in the reaction below.

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

74) Which of the following is the repeat unit for the polymer produced in the reaction shown?

A) I

B) II

C) III

D) IV

Diff: 1

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

75) Polymethyl methacrylate (PMMA) is a light, shatter-resistant plastic prepared by the free-radical polymerization of methyl methacrylate, which is shown. What is the repeat unit of PMMA?

A) I

B) II

C) III

D) IV

Diff: 2

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

76) Polychloroprene (Neoprene) can be prepared by the free-radical polymerization of chloroprene. Which choice shows a resonance structure that is formed during the propagation steps that lead to the isomerization of polychloroprene shown below?

A) I

B) II

C) III

D) II and III

E) III and IV

Diff: 3

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

77) Propylene (propene) undergoes free radical polymerization with benzoyl peroxide, but does not produce very long chains. What is the most reasonable explanation for this result?

A) There are C-H bonds at allylic positions in propylene.

B) There is a double bond in propylene.

C) The chain is not able to undergo hydrogen abstraction.

D) There are C-C bonds at vinylic positions in propylene.

E) Polypropylene has very few H-C bonds.

Diff: 2

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

78) Which choice accurately uses arrows to show termination by coupling of two growing polyvinyl chloride (PVC) chains?

A) I

B) II

C) III

D) II and III

E) III and IV

Diff: 1

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

79) Azobisisobutyronitrile (AIBN) is commonly used as a radical initiator. Which of the following choices accurately uses arrows to show this process?

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

80) Which monomer is used for the synthesis of Teflon?

A) 1,1-difluoroethene

B) 1,1,2,2-tetrafluoropropene

C) 1,1,2,2-tetrafluoroethene

D) tetrafluoromethane

Diff: 1

Learning Objective: 10.11 Describe the mechanism of the radical polymerization of ethylene, the stages of the process, and the product

81) Which monomer is used for the synthesis of poly(vinyl chloride)?

A) 1-chloroethene

B) 1-chloroethane

C) 1,2-dichloroethene

D) 1-chloro-1-propene

Diff: 1

Learning Objective: 10.12 Define cracking, hydrocracking, and reforming

82) Thermal cracking of butane can produce ethyl radicals via homolytic cleavage. Does the reaction below correctly use arrows to show this process?

A) Yes, because movement of pairs of electrons is shown using fishhook arrows.

B) Yes, because the cleavage is uneven.

C) Yes, because fishhook arrows show movement of individual electrons to produce two equal halves that each have an unpaired electron.

D) No, because fishhook arrows should not be used for reactions that show homolytic cleavage.

E) No, because fishhook arrows are not appropriate to show the movement of electrons in this type of radical reaction.

Diff: 1

Learning Objective: 10.12 Define cracking, hydrocracking, and reforming

83) Does the reaction below correctly use arrows to show the movement of electrons during the thermal cracking of hexane to yield 1-butene?

A) Yes, because the presence of a radical electron means that a double bond will be formed in the product.

B) Yes, because the radical electron moves left to join a second electron to form a double bond and a right-hand electron moves left to form an unpaired electron at the end of the left-hand fragment.

C) Yes, because the radical in the reactant is left in place in the product.

D) No, because no cracking occurs when the new double bond is formed.

E) No, because the three arrows shown do not move electrons in such a way that a bond will be broken.

Diff: 1

Learning Objective: 10.12 Define cracking, hydrocracking, and reforming

84) Which choice shows the product of coupling of the following radicals?

A) I

B) II

C) III

D) IV

E) V

Diff: 1

Learning Objective: 10.12 Define cracking, hydrocracking, and reforming

85) What would be an appropriate series of steps to synthesize 1-iodo-2-methylpropane from 2-methylpropene?

A) NBS/hv followed by I2

B) HBr/ROOR followed by KI

C) Br2/ROOR followed by NaCl

D) Br2/hv followed by KI

E) KI followed by HBr/hv

Diff: 1

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

86) Which of the choices could be used to synthesize 2-methylpropene from 2-methylpropane.

A) KI followed by Br2/ROOR

B) NaOH followed by NBS

C) Br2/hv followed by NaOEt

D) Cl2/hv

E) NBS/hv

Diff: 1

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

87) Which of the following could be used to synthesize polyethylene from ethane?

A) Br2/ hv, then KOtBu, then ROOR

B) KOtBu, then Br2/hv, then ROOR

C) HBr followed by Br2/hv

D) NBS followed by ROOR

E) NaCl followed by KI

Diff: 2

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

88) Which option is a reasonable synthesis of 3,4-dimethyl-2-pentanol using 2-methyl-2-butene and ethanol as your sources of carbon?

A) KOH/

B) HBr/ROOR followed by 1. Mg, 2. CH3CHO, 3. H3O+.

C) NBS/hv followed by HBr/ROOR

D) MgBrCH3

E) NaOH followed by Br2/hv

Diff: 2

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

89) Which sequence of reactions could be used to accomplish the given synthesis?

A) 1. Br2, light; 2. potassium t-butoxide; 3. mCPBA; 4. H3O+

B) 1. CH3MgBr; 2. NBS; 3. NaOH

C) 1. HBr, light; 2. NaOH; 3. H3O+

D) 1. HBr; 2. potassium t-butoxide; 3. mCPBA; 4. H3O+

E) 1. NaOH; 2. potassium t-butoxide; 3. H3O+

Diff: 2

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

90) Which sequence of reactions could be used to accomplish the given synthesis?

A) Br2/ROOR followed by excess NaNH2/NH3

B) HBr/ROOR followed by HBr/ROOR

C) 2 HBr/ROOR followed by 1. CH2O; 2/ H3O+

D) hv/NBS followed by HBr/ROOR

E) 2 Br2/light, followed by excess NaNH2/NH3, then 1. CH2O; 2/ H3O+

Diff: 2

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

91) Which sequence of reactions could be used to accomplish the following synthesis?

A) 1. Br2, light; 2. KOtBu; 3. HBr, ROOR; 4. NaCN

B) NaCN followed by H3O+, then treated with peroxide

C) 2 Br2/light, followed by excess NaNH2/NH3, then 1. CH2O; 2/ H3O+

D) CH3MgBr followed by excess NaNH2/NH3, then Br2/light

Diff: 2

Learning Objective: 10.13 Discuss the uses of radical halogenation in syntheses

92) Propose a sequence of reactions to accomplish the following synthesis.

A) Br2, light; 2. KOtBu; 3.O3; 4 DMS

B) 2 Br2/light, followed by excess NaNH2/NH3, then 1. CH2O; 2/ H3O+

C) HBr/light, followed by NaOH then H3O+

D) CH3COOH, then H2/Pt

E) NBS/hv followed by O3 and then H3O+

Diff: 3

Learning Objective: Spectroscopy

93) Methylenecyclopentane can be exposed to allylic bromination conditions to give multiple regioisomeric compounds, including Compound X. Compound X can then be hydrogenated to give Compound Y, which has only 4 distinct resonances in the proton-decoupled 13C NMR spectrum. What are the structures of compounds X and Y?

A) Compound X is I and compound Y is II

B) Compound X is II and compound Y is I

C) Compound X is III and compound Y is II

D) Compound X is III an compound Y is IV

E) Compound X is IV and compound Y is III

Diff: 2

Learning Objective: Spectroscopy

94) When 2-methyl-1-propene is exposed to NBS and UV light, only one major product is obtained. How many distinct resonances in the proton-decoupled 13C NMR spectrum are observed in the product?

A) 1

B) 2

C) 4

D) 6

E) 12

Diff: 2

Learning Objective: Spectroscopy

95) When 1,1,4-trimethylcyclohexane is exposed to Br2 and UV light, only one major product is obtained. How many distinct resonances in the proton-decoupled 13C NMR spectrum are observed in the product?

A) 1

B) 2

C) 4

D) 6

E) 12

Diff: 2

Learning Objective: Spectroscopy

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