ch15 organic chemistry

Chapter Fifteen

MULTIPLE CHOICE QUESTIONS

Topic: Mechanisms and IntermediatesSection: 15.2Difficulty Level: Medium

1. Which of these is the rate-determining step in the nitration of benzene?A) Protonation of nitric acid by sulfuric acidB) Protonation of sulfuric acid by nitric acidC) Loss of a water molecule by the protonated species to produce the nitronium ionD) Addition of the nitronium to benzene to produce the arenium ionE) Loss of a proton by the arenium ion to form nitrobenzeneAns: D

Topic: Other EAS ConsiderationsSection: 15.2Difficulty Level: Medium

2. In electrophilic aromatic substitution, the attacking species (the electrophile) necessarily is a:A) neutral species.B) positively charged species.C) lewis acid.D) proton.E) carbocation.Ans: C

Topic: Other EAS ConsiderationsSection: 15.3Difficulty Level: Easy

3. The electrophilic bromination or chlorination of benzene requires, in addition to the halogen:A) a hydroxide ion.B) a Lewis base.C) a Lewis acid.D) peroxide.E) ultraviolet light.Ans: C

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Topic: Synthesis Section: 15.3 Difficulty Level: Easy

4. Consider the following reaction: what is the expected product?

A) IB) IIC) IIID) IVE) VAns: B

Topic: Functional Group TestsSections: 14.2 ,14.3 and 15.3Difficulty Level: Medium

5. Which reagent would you use as the basis for a simple chemical test that would distinguish between toluene and vinylbenzene (C6H5CH=CH2)?A) NaOH/H2OB) Br2/CCl4

C) NaBH4

D) HCl/H2OE) NaI in acetoneAns: B

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Topic: Nomenclature, Functional Group TestsSection: 14.2 , 14.11 and 15.3Difficulty Level: Medium

6. Which reagent or test could you use to distinguish between phenylacetylene and vinylbenzene?A) NaOH/H2OB) Br2/CCl4

C) IR SpectroscopyD) CrO3/H2SO4

E) Concd. H2SO4

Ans: C

Topic: SynthesisSection: 15.6Difficulty Level: Easy

7. Which of the following reactions could be used to synthesize tert-butylbenzene?A)

B)

C)

D) All of the aboveE) None of the aboveAns: D

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Topic: SynthesisSection: 15.6Difficulty Level: Medium

8. Which of the following reactions would yield isopropylbenzene as the major product?A)

B)

C)

D)

E) All of theseAns: E


9. Which of the following reactions would produce isopropylbenzene?A)

B)

C)

D)


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Topic: SynthesisSection: 15.6Difficulty Level: Hard

10. Which of the following reactions would produce cumene?A)

B)

C)

D)



11. Which of the following reactions would yield cumene as the major product?A)

B)

C)

D)


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Topic: SynthesisSections: 11.9 and 15.6Difficulty Level: Medium

12. Which of these is a satisfactory synthesis of 1-chloro-2-phenylethane?A) C6H5CH2CH3 + Cl2, Fe B) C6H5CH2CH3 + Cl2, 400C C) C6H5CH2CH2OH + SOCl2 D) C6H5CH=CH2 + HCl, peroxide E) C6H6 + CH3CH2Cl, AlCl3 Ans: C

Topic: SynthesisSections: 11.9 and 15.6Difficulty Level: Medium

13. Which of these is a satisfactory synthesis of 1-chloro-2-phenylethane?A) C6H5CH2CH3 + Cl2, Fe B) C6H5CH2CH3 + Cl2, 400C C) C6H5CH2CH2OH + PCl5 D) C6H5CH=CH2 + HCl, peroxide E) C6H6 + CH3CH2Cl, AlCl3 Ans: C

Topic: Nomenclature, Reaction ProductsSection: 14.2 and 15.6Difficulty Level: Hard

14. What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and HF? A) butylbenzeneB) 2-phenylbutaneC) 2-methyl-1-phenylpropaneD) t-butylbenzeneE) 2,2-diphenylbutaneAns: B

Topic: Nomenclature, Reaction ProductsSection: 14.2 and 15.6 Difficulty Level: Hard

15. What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and AlCl3? A) butylbenzene

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B) 2-phenylbutaneC) 2-methyl-1-phenylpropaneD) t-butylbenzeneE) 2,2-diphenylbutaneAns: B


16. Which of these liquids would be unsuitable as an inert solvent for a Friedel-Crafts reaction?A) ChlorobenzeneB) NitrobenzeneC) AcetophenoneD) (Trifluoromethyl)benzeneE) All could be used.Ans: A


17. Undesired polysubstitution of an aromatic nucleus is most likely to be encountered in the case of:A) Friedel-Crafts alkylationB) Friedel-Crafts acylationC) NitrationD) SulfonationE) ChlorinationAns: A

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18. This molecule does not normally participate as a reactant in a Friedel-Crafts reaction.A) BenzeneB) ChlorobenzeneC) NitrobenzeneD) TolueneE) tert-ButylbenzeneAns: C


19. Which one of these molecules can be a reactant in a Friedel-Crafts reaction?A) AnilineB) NitrobenzeneC) ChloroetheneD) BromobenzeneE) p-BromonitrobenzeneAns: D

Topic: Nomenclature, Reaction ProductsSection: 14.2, 15.3, and 15.8 Difficulty Level: Hard

20. A mixture of chlorobenzene (1 mol) and acetanilide (1mol) is allowed to react with Br2 (0.5 mol) in the presence of trace amounts of FeBr3. What is the principal product of the competing reactions?A) 1-bromo-4-chlorobenzeneB) 1-bromo-2-chlorobenzeneC) 1-bromo-3-chlorobenzeneD) 4-bromoacetanilideE) 3-bromoacetanilideAns: D

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Topic: Reaction ProductsSection: 15.6 and 15.8 Difficulty Level: Easy

21. Which of the following reactions would give the product(s) indicated in substantial amounts (i.e., in greater than 50% yield)?

A) IB) IIC) IIID) All of theseE) None of theseAns: E

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Topic: Reaction ProductsSection: 15.6 and 15.8Difficulty Level: Medium

22. What would you expect to be the major product obtained from the following reaction?

A) IB) IIC) IIID) IVE) VAns: E

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Topic: Reaction ProductsSection: 15.6 and 15.8 Difficulty Level: Hard

23. The reaction of benzene with (CH3)3CCH2Cl in the presence of anhydrous aluminum chloride produces principally which of these?


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24.

The reaction of benzene with in the presence of anhydrous aluminum chloride produces principally which of these?

A) IB) IIC) IIID) IVE) VAns: D

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25.

The reaction of benzene with in the presence of anhydrous aluminum chloride produces principally which of these?

A) IB) IIC) IIID) IVE) VAns: A

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27. The major product(s) of the following reaction,

would be:A) IB) IIC) IIID) IVE) VAns: E

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Topic: Reaction ProductsSection: 15.7 and 15.8 Difficulty Level: Medium

28. What might be predicted to happen when the following substance undergoes Friedel-Crafts acylation?

A) Substitution occurs in ring B, p- to the methylene group.B) Substitution occurs in ring A, o- to the nitro group.C) Substitution occurs in ring A, o- to the methylene group.D) Substitution occurs in ring B, m- to the methylene group.E) None of the above. No reaction will occur.Ans: A


29. What would be the product of the following reaction sequence?


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32. Which would be the product of the following reaction sequence?

A) IB) IIC) IIID) IVE) VAns: C

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33. Which would be the product of the following reaction sequence?


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34. Which would be the product, X, of the following reaction sequence?


Topic: Directing EffectsSection: 15.10Difficulty Level: Easy

35. Which of the following is not a meta-directing substituent when present on the benzene ring?A) -NHCOCH3

B) -NO2

C) -N(CH3)3+

D) -CNE) -CO2HAns: A

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36. Which of the following compounds would yield the greatest amount of meta product when subjected to ring nitration?



37. Which of the following is not an ortho-para director in electrophilic aromatic substitution?A) -CF3

B) -OCH3

C) -CH3

D) -FE) -NH2

Ans: A

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38. Which is the best prediction of the site(s) of substitution when 3-methylphenol is nitrated?A) C-2B) C-4C) C-5D) C-6E) C-4 and C-6Ans: E


39. (Trifluoromethyl)benzene, C6H5CF3, willA) nitrate rapidly in the ortho-para positions.B) nitrate slowly in the ortho-para positions.C) nitrate rapidly in the meta position.D) nitrate slowly in the meta position.E) fail to nitrate under any conditions.Ans: D

Topic: Directing EffectsSection: 15.10Difficulty Level: Medium

40. Which of these compounds gives essentially a single product on electrophilic substitution of a third group?A) p-chlorotolueneB) m-ethylanisoleC) 1-bromo-2-chlorobenzeneD) m-xyleneE) 3-hydroxybenzoic acidAns: D

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41. Arrange the following compounds in order of decreasing reactivity in electrophilic substitution:

A) V > II > I > III > IVB) II > V > III > I > IVC) IV > I > III > V > IID) III > II > I > IV > VE) IV > V > II > I > IIIAns: B

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42. The major product(s), D, of the following reaction,

would be:A) IB) IIC) IIID) IVE) Approximately equal amounts of I and IIAns: D

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A) IB) IIC) IIID) IVE) Equal amounts of II and IVAns: C

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A) IB) IIC) IIID) IVE) Equal amounts of II and IVAns: C

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50. What would you expect to be the major product obtained from the monobromination of m-dichlorobenzene?

A) IB) IIC) IIID) Equal amounts of I and IIE) Equal amounts of I, II and IIIAns: B


51. Which would be the major product(s) of the following reaction?

A) IB) IIC) IIID) I and II in roughly equal amountsE) I and III in roughly equal amountsAns: A

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Topic: ReagentsSection: 15.3 and 15.10Difficulty Level: Medium

52. Which reagent(s) would you use to carry out the following transformation?isopropylbenzene 2- and 4-chloro-1-isopropylbenzeneA) Cl2, light, and heatB) Cl2, FeCl3

C) SOCl2

D) C2H5Cl, AlCl3

E) HCl, peroxidesAns: B


53. Which reagent(s) would you use to carry out the following transformation?ethylbenzene 2- and 4-chloro-1-ethylbenzeneA) Cl2, light, and heatB) Cl2, FeCl3

C) SOCl2

D) C2H5Cl, AlCl3

E) None of theseAns: B


54. Which reagent(s) would you use to carry out the following transformation?t-butylbenzene p-chloro substitution productA) Cl2, light, and heatB) Cl2, FeCl3

C) SOCl2

D) C2H5Cl, AlCl3

E) HCl, peroxideAns: B

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55. Which reagent(s) would you use to synthesize 2- and 4-bromo-1-cyclopentylbenzene from cyclopentylbenzene?A) N-Bromosuccinimide (NBS), CCl4, lightB) PBr3

C) Br2, FeBr3

D) CH3CH2Br, AlBr3

E) HBr, ROORAns: C

Topic: ReagentsSection: 15.3 and 15.10Difficulty Level: Hard

56. Which reagent(s) would you use to carry out the following transformation?cumene 2- and 4-chlorocumeneA) Cl2, light, and heatB) Cl2, FeCl3

C) SOCl2

D) C2H5Cl, AlCl3

E) HCl, peroxidesAns: B

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59. What would be the major product(s) of the following reaction?

A) IB) IIC) IIID) IVE) Approximately equal amounts of II and IVAns: C

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62. What would you expect to be the major product(s) obtained from the mononitration of m-dichlorobenzene?

A) IB) IIC) IIID) Equal amounts of I and IIE) Equal amounts of I, II and IIIAns: B


63. What would you expect to be the major product(s) obtained from the following reaction?

A) IB) IIC) IIID) IVE) Equal amounts of I and IIAns: C

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64. The major product(s), D, of the following reaction

would be:A) IB) IIC) IIID) IVE) Equal amounts of I and IIAns: D

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Topic: Reaction ProductsSection: 15.4 and 15.10Difficulty Level: Hard



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A) IB) IIC) IIID) Equal amounts of I and IVE) Equal amounts of II and IVAns: C

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A) IB) IIC) IIID) Equal amounts of I and IVE) Equal amounts of II and IVAns: C

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70. The major product(s), C, of the following reaction,

would be:A) IB) IIC) IIID) Approximately equal amounts of I and IIE) Approximately equal amounts of I and IIIAns: B


71. Which reagent would you use to carry out the following transformation?tert-butylbenzene p-tert-butylbenzenesulfonic acid

+o-tert-butylbenzenesulfonic acid

A) HNO3/H2SO4

B) tert-C4H9Cl/AlCl3

C) H2SO3/peroxidesD) SO3/H2SO4

E) SO2/H2SO3

Ans: D

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Topic: Relative ReactivitiesSection: 15.11Difficulty Level: Easy

72. Which of the following compounds would be most reactive toward electrophilic substitution?



73. Which of the following compounds would be least reactive toward electrophilic substitution?


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74. Which of the following compounds would be most reactive to ring bromination?



75. Which of the following compounds would be least reactive toward electrophilic substitution?


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76. Which of the following compounds would be most reactive toward electrophilic substitution?



77. Which of the following compounds would be most reactive toward ring nitration?


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78. Which of the compounds listed below would you expect to give the greatest amount of meta-product when subjected to ring bromination?



79. Which of the following compounds would be most reactive toward ring bromination?


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80. Which of the compounds listed below would you expect to give the greatest amount of meta-product when subjected to ring nitration?


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81. Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when bromobenzene undergoes para-chlorination?

A) IB) IIC) IIID) IVE) All of the aboveAns: E

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82. Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when chlorobenzene undergoes para-chlorination?



83. Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when acetanilide undergoes para-bromination?


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84. Which of the following contributors to the resonance stabilized hybrid formed when aniline undergoes para-chlorination would be exceptionally stable?

A) IB) IIC) IIID) IVE) None of theseAns: B


85. Consider the structures given below. Which of them would be a relatively stable contributor to the hybrid formed when toluene undergoes para bromination?


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86. Which of the following structures does not contribute to the resonance hybrid of the intermediate formed when nitrobenzene undergoes meta-chlorination?

A) IB) IIC) IIID) None of these contributeE) All of these contributeAns: E

Topic: Relative ReactivitiesSection: 15.11Difficulty Level: Medium

87. Which of the following compounds would you expect to be most reactive toward ring nitration?A) BenzeneB) TolueneC) m-XyleneD) p-XyleneE) Benzoic acidAns: C

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Topic: Relative ReactivitiesSection: 15.11Difficulty Level: Medium

88. Which of the following compounds would you expect to be most reactive toward ring nitration?A) BenzeneB) TolueneC) m-XyleneD) o-XyleneE) Benzoic acidAns: C


89. What is a feature found in all ortho-para directing groups?A) An oxygen atom is directly attached to the aromatic ring.B) The atom attached to the aromatic ring possesses an unshared pair of electrons.C) The group has the ability to delocalize the positive charge of the arenium ion.D) The atom directly attached to the aromatic ring is more electronegative than

carbon.E) The group contains a multiple bond.Ans: C

Topic: Directing EffectsSection: 15.10 and 15.11Difficulty Level: Easy

90. What feature is common to all meta-directing groups?A) The atom directly attached to the ring has a full or well-developed partial positive

charge.B) The atom directly attached to the ring is doubly bonded to oxygen.C) One or more halogen atoms are present in the group.D) One or more oxygen atoms are present in the group.E) The group is attached to the ring through a carbon atom.Ans: A

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Topic: Other EAS ConsiderationsSection: 15.10 and 15.11Difficulty Level: Medium

91. This substituent deactivates the benzene ring towards electrophilic substitution but directs the incoming group chiefly to the ortho and para positions.A) -OCH2CH3

B) -NO2

C) -FD) -CF3

E) -NHCOCH3

Ans: C

Topic: Reaction ProductsSection: 15.12Difficulty Level: Medium

92. The major product(s), A, of the following reaction,

would be:A) IB) IIC) A mixture of I and IID) IIIE) IVAns: E

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A) IB) IIC) A mixture of I and IID) IIIE) IVAns: A

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A) IB) IIC) A mixture of I and IID) IIIE) IVAns: D

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95. The major product(s), A, of the following reaction,

would be:A) IB) IIC) A mixture of I and IID) IIIE) IVAns: E


96. What would be the major product of the following reaction?

A) IB) II

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C) IIID) IVE) VAns: C



A) I

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B) IIC) IIID) IVE) VAns: D

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Topic: Reaction ProductsSection: 15.12 Difficulty Level: Medium

101. 4 of the following reaction?


Topic: ReagentsSection: 15.12 Difficulty Level: Medium

102. Which reagent(s) would you use to carry out the following transformation?ethylbenzene 1-chloro-1-phenylethaneA) Cl2, light, or heatB) Cl2, FeCl3

C) SOCl2

D) C2H5Cl, AlCl3

E) HCl, O2

Ans: A

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Topic: Non-EAS Relative Rates and IntermediatesSection: 15.12Difficulty Level: Medium

103. Which of the following structures would not be a contributor to the resonance hybrid of the benzyl cation?



104. Which of the following carbocations would be most stable?A)

B)

C)

D)

E)

Ans: E

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Topic: ReagentsSection: 15.12 Difficulty Level: Hard

105. Which reagent(s) would you use to carry out the following transformation?toluene benzyl bromideA) Br2, FeBr3

B) N-Bromosuccinimide, ROOR, hC) HBrD) Br2/CCl4

E) NaBr, H2SO4

Ans: B


106. When toluene is reacted in turn with 1) Cl2 (large excess), heat, and light and 2) Br2,FeBr3, the chief product is:

A) IB) IIC) IIID) IVE) A mixture of III and IVAns: B

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107. Benzoic acid can be prepared by the oxidation of all of the following compounds except this one:A) C6H5CH=CH2

B) C6H5CCHC) C6H5COCH3

D) C6H5CH2CH2CH3

E) C6H5C(CH3)3

Ans: E


108. Benzoic acid can be prepared by the oxidation of which of the following compounds:A) C6H5CH=CH2

B) C6H5CCHC) C6H5COCH3

D) C6H5CH2CH2CH3



109. Which reagent(s) would you use to carry out the following transformation?toluene benzoic acidA) Br2, heat, and lightB) Cl2, FeCl3

C) KMnO4, OH-, heat (then H3O+)D) HNO3/H2SO4

E) SO3/H2SO4

Ans: C

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110. Which reagent(s) would you use to carry out the following transformation?ethylbenzene benzoic acidA) Cl2, light, and heatB) Cl2, FeCl3

C) KMnO4, OH-, heat (then H3O+)D) HNO3/H2SO4

E) SO3/H2SO4

Ans: C


111. Which of these is a satisfactory synthesis of 1-bromo-2-phenylethane?A) C6H5CH2CH3 + Br2, Fe3+ B) C6H5CH2CH3 + Br2, 400C C) C6H5CH2CH2OH + Br2, CCl4 D) C6H5CH=CH2 + HBr, ROOR E) C6H5CH2CH3 + NBS, ROOR Ans: D

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Topic: Reaction ProductsSection: 15.3, 15.4, 15.10, and 15.13 Difficulty Level: Hard

112. Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O+ (2) HNO3, H2SO4 (3) Br2, FeBr3

What is the final product of this sequence?


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Topic: Reaction ProductsSection: 15.3, 15.4, 15.10, and 15.13 Difficulty Level: Hard

113. Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O+ (2) HNO3, H2SO4 (3) Cl2, FeCl3

What is the final product of this sequence?


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Topic: Reaction productsSection: 15.6, 15.12, 15.13 and previous chaptersDifficulty Level: Hard

114. What product would result from the following series of reactions,


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Topic: Reaction ProductsSection: 15.6, 15.12, 15.13 and previous chaptersDifficulty Level: Hard



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Topic: Reaction ProductsSection: 15.6, 15.12, 15.13 and previous chaptersDifficulty Level: Hard



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Topic: Synthesis Section: 15.13C Difficulty Level: Medium

117. What reagent can effect the following transformation?

A) CO2; then H3O+

B) H3O+, heatC) Mg; then CO2; then H3O+

D) H2O2, heatE) KMnO4, OH-, heat; then H3O+

Ans: E


118. Each of the five disubstituted benzenes shown below is nitrated. In which of these cases does the arrow not indicate the chief position of nitration.


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Topic: SynthesisSection: 15.14 Difficulty Level: Medium

119. A good synthesis of

would be:A)

B)

C)

D) More than one of theseE) None of theseAns: B

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120. Which would be a good synthesis of m-nitrobenzoic acid?A)

B)

C)

D) More than one of the aboveE) None of the aboveAns: C

Topic: ReagentsSection: 15.14Difficulty Level: Hard

121. The compound 4-bromo-1-propylbenzene is best made from benzene by the application of these reagents in the order shown:A) (1) Br2,Fe (2) CH3CH2CH2Cl, AlCl3

B) (1) CH3CH2CH2Cl, AlCl3 (2) Br2,FeC)

D)

E) (1) (CH3)2CHCl, AlCl3 (2) Br2,FeAns: D

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Topic: Nomenclature, SynthesisSection: 15.14Difficulty Level: Hard

122. Which of the following would be the best synthesis of 1,4-dimethyl-2-nitrobenzene?A)

B)

C)

D)

E) All of these are equally good.Ans: C


123. Starting with benzene, the best method for preparing p-nitrobenzoic acid is:A) HNO3/H2SO4; then CH3Cl/AlCl3; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+.B) CH3Cl/AlCl3; then HNO3/H2SO4; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+.C) CH3Cl/AlCl3; then KMnO4/-OH/heat, followed by H3O+; then HNO3/H2SO4.D) HNO3/H2SO4; then KMnO4/-OH/heat, followed by H3O+; then CH3Cl/AlCl3.E) HNO3/H2SO4; then CO2, followed by H3O+.Ans: B

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124. Starting with benzene, the best method for preparing m-nitrobenzoic acid is:A) HNO3/H2SO4; then CH3Cl/AlCl3; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+.B) CH3Cl/AlCl3; then HNO3/H2SO4; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+.C) CH3Cl/AlCl3; then KMnO4/-OH/heat, followed by H3O+; then HNO3/H2SO4.D) HNO3/H2SO4; then KMnO4/-OH/heat, followed by H3O+; then CH3Cl/AlCl3.E) HNO3/H2SO4; then CO2, followed by H3O+.Ans: C

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125. How might the following synthesis be carried out:

A)

B)

C)

D)

E) None of these syntheses is satisfactory.Ans: C

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126. How might the following synthesis be carried out:

A)

B)

C)

D)

E) None of these syntheses is satisfactory.Ans: D

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127. Which is the best sequence of reactions for the preparation of p-bromostyrene from ethylbenzene?A)

B)

C)

D)

E) None of these syntheses is satisfactory.Ans: B

Topic: SynthesisSection: 15.14 and previous chaptersDifficulty Level: Hard

128. Which is the best sequence of reactions for the following transformation?

A) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H3O+, heatB) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4

C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heatD) i) HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heatE) None of these syntheses is satisfactory.Ans: A

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A) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H2O, NH4ClB) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4




A) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H2O, NH4ClB) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4


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A) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H3O+, heatB) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4

C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heatD) i)HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heatE) None of these syntheses is satisfactory.Ans: A



A) i) HNO3, H2SO4; ii) 2EtMgBr, Et2O; iii) NH4ClB) i) 2EtMgBr, Et2O; ii) H3O+; iii) HNO3, H2SO4

C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) 2EtMgBr, Et2OD) i) LAH; ii) 2EtLi, Et2O; iii) HNO3, H2SO4, heatE) None of these syntheses is satisfactory.Ans: A

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A) i) HNO3, H2SO4; ii) 2EtMgBr, Et2O; iii) NH4ClB) i) 2EtMgBr, Et2O; ii) H3O+; iii) HNO3, H2SO4

C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) 2EtMgBr, Et2OD) i) LAH; ii) 2EtLi, Et2O; iii) HNO3, H2SO4, heatE) None of these syntheses is satisfactory.Ans: A

Topic: SynthesisSection: 15.14 Difficulty Level: Hard


A) i) SOCl2; ii) C6H6, AlCl3; iii) Zn(Hg),HCl; iv) HNO3, H2SO4

B) i) SOCl2; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) H2, NiC) i) HNO3, H2SO4; ii) SOCl2; iii) C6H6, AlCl3; iv) Zn(Hg),HClD) i) PBr3; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) NaBH4, H2OE) Two of these syntheses are satisfactory.Ans: C

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135. Which alkyl halide would be most reactive in an SN2 reaction?A) C6H5CH2CH2CH2BrB)

C)

D)

E)

Ans: A


136. Which alkyl halide would be most reactive in an SN1 reaction?A) C6H5CH2CH2CH2BrB)

C)

D)

E)

Ans: D

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Topic: Non-EAS ReactionsSection: 15.15Difficulty Level: Medium

137. SN1 solvolysis of C6H5CH=CHCH2Cl in water produces:A) C6H5CH2C(OH)=CH2

B) C6H5CH=CHCH2OH C) C6H5CHOHCH=CH2

D) A mixture of B) and C)E) A mixture of A), B) and C)Ans: D


138. Which compound is capable of undergoing both SN1 and SN2 reactions in ordinary nonacidic solvents?


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139. Which alkyl halide can undergo both SN1 and SN2 reactions in nonacidic solvents?A) CH3BrB) CH3CH2CH2BrC)

D) C6H5CH2CH2CH2BrE)

Ans: C


140. The rate of solvolysis in ethanol is least for which of these compounds?A) C6H5CH2ClB)

C) (C6H5)2CHClD)

E) (C6H5)3CClAns: A

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Topic: Directing EffectsSection: 15.10 and 15.15Difficulty Level: Medium

141. The ortho/para product ratio is expected to be the smallest for the bromination of which of these?A) TolueneB) IsopropylbenzeneC) ButylbenzeneD) sec-ButylbenzeneE) tert-ButylbenzeneAns: E


142. What is the Birch reduction product of the following reaction?


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Topic: Non-EAS Relative Rates and IntermediatesSection: 15.16Difficulty Level: Hard

143. Which of these species is/are proposed as intermediate(s) in the mechanism for the Birch reduction?A) RadicalB) CarbanionC) Radical anionD) Both A) and B)E) All of A), B) and C)Ans: E

SHORT ANSWER QUESTIONS

Topic: General ReactivitySection: 14.3 and 15.1Difficulty Level: Easy

144. Although benzene is susceptible to electrophilic attack, its special stability causes it to undergo ______________ rather than ____________ reactions.Ans: substitution; addition

Topic: General ReactivitySection: 15.2Difficulty Level: Easy

145. Benzene is susceptible to electrophilic attack primarily because of its _____________.Ans: exposed system

Topic: EAS MechanismSection: 15.2Difficulty Level: Easy

146. In general, there are three steps to an electrophilic aromatic substitution reaction. These are:a) formation of an _____________;b) reaction with an aromatic ring to form an ___________; andc) loss of a _________ to reform the aromatic system.Ans: electrophile; arenium ion; proton

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Topic: Synthetic StrategySection: 15.7 and previous chaptersDifficulty Level: Medium

147. Suggest a reasonable synthetic strategy for the synthesis of 4-methyl-1-phenyl-1-pentanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COClAns:

Topic: General ReactivitySection: 15.8Difficulty Level: Easy

148. Aryl and vinyl halides cannot be used in the Friedel-Crafts alkylation because they do not __________.Ans: form carbocations readily

Topic: Mechanism, Carbocation StabilitySection: 15.6 and 15.8Difficulty Level: Hard

149. Draw a mechanism that explains the formation of the following product in this Friedel-Crafts alkylation:

Ans:

Topic: General EAS Reactivity

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Section: 15.10Difficulty Level: Easy

150. Substituent groups affect both _____________ and _______________ in electrophilic aromatic substitution reactions.Ans: reactivity; orientation

Topic: General EAS ReactivitySection: 15.10Difficulty Level: Easy

151. Electron-donating groups increase the electron density on the aromatic ring, causing it to be more reactive than benzene itself towards EAS. These types of groups are called _____________ groups.Ans: activating


152. Electron-withdrawing groups decrease the electron density on the aromatic ring, causing it to be less reactive than benzene itself towards EAS. These types of groups are called _____________ groups.Ans: deactivating


153. With the exception of halogens, activating groups are ____________ directors and deactivating groups are _________ directors.Ans: ortho/para; meta

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Topic: General EAS ReactivitySection: 15.2 and 15.11Difficulty Level: Hard

154. Based on your knowledge of electrophilic aromatic substitution, predict the preferential position of attack of an electrophile on furan, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?

Ans:The 2 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three resonance forms vs. only two for the 3 substituted product), and hence will form faster.

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155. Based on your knowledge of electrophilic aromatic substitution, predict the preferential position of attack of an electrophile on pyrrole, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?Ans:The 2 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three resonance forms vs. only two for the 3 substituted product), and hence will form faster.

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156. Based on your knowledge of electrophilic aromatic substitution, predict the preferential position of attack of an electrophile on thiophene, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?Ans:The 2 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three resonance forms vs. only two for the 3 substituted product), and hence will form faster.

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157. Based on your knowledge of electrophilic aromatic substitution, predict the position of attack of an electrophile on pyridine, i.e., does the electrophile E+ attack carbon 2, 3, or 4? Explain your answer.

Which substitution product(s) forms and why?Ans:The 3 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three good resonance forms), and hence will form faster.

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158. Based on your knowledge of electrophilic aromatic substitution, predict the preferential position of nitration of naphthalene, i.e., does the NO2

+ attack carbon 1, or 2? Explain your answer.

Which substitution product forms preferentially and why?Ans:The 1 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses two benzylic type resonance forms vs. only one for the 2 substituted product), and hence will form faster.

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Topic: General EAS Reactivity, Mechanisms, Energy DiagramsSection: 15.2 and 15.11Difficulty Level: Hard

159. Using a potential energy diagram, explain/illustrate the preferential formation of the 3 substituted product instead of the 2 or 4 product in the electrophilic aromatic substitution of pyridine.

Ans:The 3 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three good resonance forms), and hence will form faster.

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160. Using a potential energy diagram, explain/illustrate the preferential formation of the 1 nitrated product instead of the 2 nitrated product in the electrophilic aromatic nitration of naphthalene.

Ans:The 1 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses two benzylic type resonance forms vs. only one for the 2 substituted product), and hence will form faster.

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161. Using a potential energy diagram, explain/illustrate the preferential formation of the 2 substituted product instead of the 3 product in the electrophilic aromatic substitution of furan.

Ans:The 2 substitution product is favored since it comes from the arenium ion intermediate that is lower in energy/more stable (possesses three resonance forms vs. only two for the 3 substituted product), and hence will form faster

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162. Using a potential energy diagram, explain/illustrate the preferential formation of the 2 substituted product instead of the 3 product in the electrophilic aromatic substitution of pyrrole.


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163. Using a potential energy diagram, explain/illustrate the preferential formation of the 2 substituted product instead of the 3 product in the electrophilic aromatic substitution of thiophene.


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164. Based on your knowledge of electrophilic aromatic substitution, and assuming the pyrrole ring of indole (shown) is activated toward electrophilic aromatic substituted more so than the benzenoid ring, predict the preferential position of attack of an electrophile, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?

Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the nitrogen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity.

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165. Based on your knowledge of electrophilic aromatic substitution, and assuming the furan ring of benzo[b]furan (shown) is activated toward electrophilic aromatic substituted more so than the benzenoid ring, predict the preferential position of attack of an electrophile, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the oxygen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity.

Topic: General EAS Reactivity, Mechanisms, Energy Diagrams

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Section: 15.2 and 15.11Difficulty Level: Hard

166. Based on your knowledge of electrophilic aromatic substitution, and assuming the thiophene ring of benzo[b]thiophene (shown) is activated toward electrophilic aromatic substituted more so than the benzenoid ring, predict the preferential position of attack of an electrophile, i.e., does the electrophile E+ attack carbon 2, or 3? Explain your answer.

Which substitution product forms preferentially and why?Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the oxygen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity


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167. Using a potential energy diagram, explain/illustrate the preferential formation of the 3 substituted product instead of the 2 product in the electrophilic aromatic substitution of benzo[b] thiophene (shown).

Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the oxygen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity.

1177


168. Using a potential energy diagram, explain/illustrate the preferential formation of the 3 substituted product instead of the 2 product in the electrophilic aromatic substitution of benzo[b] furane (shown).

Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the oxygen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity.

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169. Using a potential energy diagram, explain/illustrate the preferential formation of the 3 substituted product instead of the 2 product in the electrophilic aromatic substitution of indole (shown).

Ans:3-substitution is preferred, since this leads to a carbocation intermediate that can be resonance stabilized through the nitrogen, without loss of the benzenoid ring aromaticity. This resonance form is lower in energy than those forming from the 2-substituted product, which although can be resonance stabilized through the benzenoid aromatic ring, produces resonance forms without aromaticity.

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Topic: General EAS ReactivitySection: 15.3, 15.10 and 15.11Difficulty Level: Medium

170. When the following substance is treated with Br2/FeBr3, the major product is obtained in good yield, and only very small amounts of minor products are found. What is this major product and why are the minor products not formed to any significant degree? Explain clearly.

Ans: The major products are produced by brominating Ring B. Ring B is more electron-rich due to the electron-donation of both the nitrogen and methyl groups attached versus the two electron-withdrawing carbonyl groups attached to Ring A, which make it inherently electron-poor. Therefore, bromination mainly occurs on the more electron-rich benzene ring affording a mixture of the following two compounds. Due to steric effects, bromination ortho to both the nitrogen and methyl group would lead to a minor product. Also, because Ring A is electron-poor, bromination of this ring would also lead to minor products.

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Topic: Mechanism, Carbocation StabilitySection: 15.12Difficulty Level: Hard

171. Acid-catalyzed hydration of 1-phenyl-1-pentene gives 1-phenyl-1-pentanol almost exclusively; the other possible hydration product, 1-phenyl-2-pentanol, is not detected at all. Explain clearly.Ans: Acid catalyzed hydration of an alkene occurs through a carbocation intermediate.

Although 1-phenyl-1-pentene is symmetrically substituted at the C=C, the relative stabilities of the two possible carbocation intermediates is significantly different: although both are secondary carbocations, one is also benzylic and thus stabilized by resonance. The observation that 1-phenyl-1-pentene gives 1-phenyl-1-pentanol, almost exclusively, is in accordance with the general trend that acid catalyzed hydration chiefly tends to afford products formed via the most stable intermediate carbocation.

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Topic: EAS/non-EAS ReactivitySection: 15.3 and 15.12Difficulty Level: Medium

172. When toluene reacts with Cl2, the identity of the major product(s) obtained depends on whether the reaction is carried out in the presence of catalytic amounts of FeCl3, or without catalyst, at high temp. Explain clearly.Ans: Reaction with Cl2/FeCl3 results in electrophilic aromatic substitution at the o- and

p- positions, since the methyl group in toluene is an activating, o-,p- director. In contrast, when the reaction is carried out without catalyst, at high temperature, the methyl group undergoes free-radical halogenation via the benzyl radical intermediate.


173. When two different groups are present on a benzene ring, the ____________ generally determines the outcome of an EAS reaction.Ans: more powerful activating group

Topic: Synthetic StrategySection: 15.14 and previous chaptersDifficulty Level: Medium

174. Suggest a reasonable synthetic strategy for the synthesis of 3,5-dinitrobenzyl alcohol from benzaldehyde.Ans:

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Topic: Synthetic StrategySection: 15.14 and previous chaptersDifficulty Level: Hard

175. Suggest a reasonable synthetic strategy for the synthesis of 6-methyl-3-phenyl-3-heptanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COClAns:



Ans:

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177. Propose a reasonable synthesis of the following compound from benzene.

Ans:

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178. What product would result from the following series of reactions:

Ans:

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