Chapter 15 - Test Bank Chem 200

Package Title: Solomons Test Bank Course Title: Solomons 11e Chapter Number: 15

Question Type: Multiple Choice

1) Which of these is the rate-determining step in the nitration of benzene? a) Protonation of nitric acid by sulfuric acid b) Protonation of sulfuric acid by nitric acid c) Loss of a water molecule by the protonated species to produce the nitronium ion d) Addition of the nitronium to benzene to produce the arenium ion e) Loss of a proton by the arenium ion to form nitrobenzene Answer: D Topic: Mechanisms and Intermediates Section: 15.2 Difficulty Level: Medium

2) Which of these is the rate-determining step in the sulfonation of benzene? a) Formation of SO3 from sulfuric acid b) Protonation of SO3 sulfuric acid c) Addition of SO3H+ to benzene to form the arenium ion d) Loss of a proton from the arenium ion to form benzenesulfonic acid e) None of these choices. Answer: C Topic: Mechanisms and Intermediates Section: 15.2 Difficulty Level: Medium

3) Which of these is the rate-determining step in the bromination of benzene? a) Complexation of bromine with the iron(III) bromide catalyst b) Formation of Br+ ion c) Addition of Br+ to benzene to form the arenium ion d) Loss of a proton from the arenium ion to form bromobenzene e) None of these choices.

1

Answer: C Topic: Mechanisms and Intermediates Section: 15.2 Difficulty Level: Medium

4) Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when bromobenzene undergoes para-chlorination? .. .. .. .. : Br : : Br + : Br : : Br : + + + H Cl

H Cl

H Cl

H Cl

I

II

III

IV

a) I b) II c) III d) IV e) All of these choices. Answer: E Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

5) Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when chlorobenzene undergoes para-chlorination? .. .. .. .. : Cl : : Cl + : Cl : : Cl : + + + H Cl

H Cl

H Cl

H Cl

I

II

III

IV

a) I b) II c) III d) IV e) All of these choices. Answer: E Topic: Mechanisms and Intermediates 2

Section: 15.11 Difficulty Level: Medium

6) Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when acetanilide undergoes para-bromination? +NCOCH :NHCOCH3 : NHCOCH3 : NHCOCH3 3 + + + H Br

H Br

H Br

H Br

I

II

III

IV

a) I b) II c) III d) IV e) All of these choices. Answer: E Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

7) Which of the following contributors to the resonance stabilized hybrid formed when aniline undergoes para-chlorination would be exceptionally stable? +NH2 : NH2 : NH2 : NH2 + + + H Cl

H Cl

H Cl

H Cl

I

II

III

IV

a) I b) II c) III d) IV e) None of these choices. Answer: B Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

3

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

a) I b) II c) III d) IV e) V Answer: C Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

9) Which of the following structures does not contribute to the resonance hybrid of the intermediate formed when nitrobenzene undergoes meta-chlorination? .. .. .. .. .. .. :O : O: : O : O: : O : O: N

N

+

H Cl

I

+

N

+H

H Cl

II

Cl

III

a) I b) II c) III d) None of these contribute. e) All of these contribute. Answer: E Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

10) Consider the resonance forms shown for the arenium ionformed from the bromination of acetanilide. Which resonance form contributes most to the overall resonance hybrid? 4

H I

Br

O

HN

HN

HN

Br

O

O

O

H II

Br

HN

H

H

Br IV

III

a) I b) II c) III d) IV e) All contribute equally. Answer: C Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

11) Consider the resonance forms shown for the arenium ionformed from the bromination of acetanilide. Which resonance form contributes most to the overall resonance hybrid?

a) I b) II c) III d) IV e) All contribute equally. Answer: D 5

Topic: Mechanisms and Intermediates Section: 15.11 Difficulty Level: Medium

12) 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. Answer: C Topic: Other EAS Considerations Section: 15.3 Difficulty Level: Easy

13) 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. Answer: C Topic: Other EAS Considerations Section: 15.2 Difficulty Level: Medium

14) Which of these liquids would be unsuitable as an inert solvent for a Friedel-Crafts reaction? a) Chlorobenzene b) Nitrobenzene c) Acetophenone d) (Trifluoromethyl) benzene e) All of these choices could be used. Answer: A

6

Topic: Other EAS Considerations Section: 15.8 Difficulty Level: Medium

15) Undesired polysubstitution of an aromatic nucleus is most likely to be encountered in the case of: a) Friedel-Crafts alkylation b) Friedel-Crafts acylation c) Nitration d) Sulfonation e) Chlorination Answer: A Topic: Other EAS Considerations Section: 15.8 Difficulty Level: Medium

16) 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) -F d) -CF3 e) -NHCOCH3 Answer: C Topic: Other EAS Considerations Section: 15.10 and 15.11 Difficulty Level: Medium

17) This molecule does not normally participate as a reactant in a Friedel-Crafts reaction. a) Benzene b) Chlorobenzene c) Nitrobenzene d) Toluene e) tert-Butylbenzene Answer: C 7

Topic: Other EAS Considerations Section: 15.8 Difficulty Level: Medium

18) Which one of these molecules can be a reactant in a Friedel-Crafts reaction? a) Aniline b) Nitrobenzene c) Chloroethene d) Bromobenzene e) p-Bromonitrobenzene Answer: D Topic: Other EAS Considerations Section: 15.8 Difficulty Level: Medium

19) Which one of these molecules can be a reactant in a Friedel-Crafts reaction? a) Aniline b) Benzenesulfonic acid c) Chloroethene d) Bromobenzene e) p-Bromonitrobenzene Answer: D Topic: Other EAS Considerations Section: 15.8 Difficulty Level: Medium

20) Which reagent would you use as the basis for a simple chemical test that would distinguish between toluene and vinylbenzene (C6H5CH=CH2)? a) NaOH/H2O b) Br2/CCl4 c) NaBH4 d) HCl/H2O e) NaI in acetone Answer: B 8

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

21) Which reagent or test could you use to distinguish between phenylacetylene and vinylbenzene? a) NaOH/H2O b) Br2/CCl4 c) IR Spectroscopy d) CrO3/H2SO4 e) Concd. H2SO4 Answer: C Topic: Nomenclature, Functional Group Tests Section: 14.2, 14.11 and 15.3 Difficulty Level: Medium

22) What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and HF? a) butylbenzene b) 2-phenylbutane c) 2-methyl-1-phenylpropane d) t-butylbenzene e) 2,2-diphenylbutane Answer: B Topic: Nomenclature, Reaction Products Section: 14.2 and 15.6 Difficulty Level: Hard

23) What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and AlCl3? a) butylbenzene b) 2-phenylbutane c) 2-methyl-1-phenylpropane d) t-butylbenzene e) 2,2-diphenylbutane

9

Answer: B Topic: Nomenclature, Reaction Products Section: 14.2 and 15.6 Difficulty Level: Hard

24) 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-chlorobenzene b) 1-bromo-2-chlorobenzene c) 1-bromo-3-chlorobenzene d) 4-bromoacetanilide e) 3-bromoacetanilide Answer: D Topic: Nomenclature, Reaction Products Section: 14.2, 15.3, and 15.8 Difficulty Level: Hard

25) A mixture of chlorobenzene (1 mol) and anisole (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-chlorobenzene b) 1-bromo-2-chlorobenzene c) 1-bromo-3-chlorobenzene d) 4-bromoanisole e) 3-bromoanisole Answer: D Topic: Nomenclature, Reaction Products Section: 14.2, 15.3, and 15.8 Difficulty Level: Hard

26) Which of the following reactions could be used to synthesize tert-butylbenzene? a) C6H6 + CH2=C(CH3)2

H2SO4

10

b) C6H6 + (CH3)3COH c) C6H6 + (CH3)3CCl d) All of these choices. e) None of these choices.

H2SO4 AlCl3

Answer: D Topic: Synthesis Section: 15.6 Difficulty Level: Easy

27) Which of the following reactions could be used to synthesize tert-butylbenzene? a) C6H6 + CH2=C(CH3)2

H2SO4

b) c) C6H6 + (CH3)3CCl d) All of these choices. e) None of these choices.

AlCl3

Answer: D Topic: Synthesis Section: 15.6 Difficulty Level: Easy

28) Which of the following reactions could be used to synthesize tert-butylbenzene?

a) b) c) C6H6 + (CH3)3CCl d) All of these choices. e) None of these choices.

AlCl3

Answer: D Topic: Synthesis 11

Section: 15.6 Difficulty Level: Easy

29) Consider the following reaction: what is the expected product? NH2

Br2, H2O

?

Cl Cl

NH2 Br

Br

H2 N

Cl

Br

Br

Cl

NH2

II

I

Br

Br

III

NH2

NH2 Br

Br Br

Cl

Cl

IV

V

a) I b) II c) III d) IV e) V Answer: B Topic: Synthesis Section: 15.3 Difficulty Level: Easy

30) Which of the following reactions would yield isopropylbenzene as the major product? CH3CHCH3

Benzene

b)

OH

H2SO4 CH3CHCH3

Benzene

c)

Cl

AlCl3

12

Benzene

CH3CH2CH2Cl

AlCl3 d) e) All of these choices. Answer: E Topic: Synthesis Section: 15.6 Difficulty Level: Medium

31) Which of the following reactions would yield isopropylbenzene as the major product?

a) CH3CHCH3

Benzene

b)

OH

H2SO4 CH3CHCH3

Benzene

c)

Cl

AlCl3 CH3CH2CH2Cl

Benzene AlCl3 d) e) All of these choices. Answer: E Topic: Synthesis Section: 15.6 Difficulty Level: Medium

32) Which of the following reactions would yield isopropylbenzene as the major product?

a)

13

b) CH3CHCH3

Benzene

c)

Benzene

Cl

AlCl3 CH3CH2CH2Cl

AlCl3 d) e) All of these choices. Answer: E Topic: Synthesis Section: 15.6 Difficulty Level: Medium

33) Which of the following reactions would produce isopropylbenzene? Cl

Benzene

a) Benzene

b)

AlCl3 HF OH

Benzene H2SO4

c)

Br

Benzene

AlCl3 d) e) All of these choices. Answer: E Topic: Synthesis Section: 15.6 Difficulty Level: Medium

34) Which of these is a satisfactory synthesis of 1-chloro-2-phenylethane? 14

a) C6H5CH2CH3 + Cl2, Fe ⎯⎯→ b) C6H5CH2CH3 + Cl2, 400°C ⎯⎯→ c) C6H5CH2CH2OH + SOCl2 ⎯⎯→ d) C6H5CH=CH2 + HCl, peroxide ⎯⎯→ e) C6H6 + CH3CH2Cl, AlCl3 ⎯⎯→ Answer: C Topic: Synthesis Sections: 11.9 and 15.6 Difficulty Level: Medium

35) Which of these is a satisfactory synthesis of 1-chloro-2-phenylethane? a) C6H5CH2CH3 + Cl2, Fe ⎯⎯→ b) C6H5CH2CH3 + Cl2, 400°C ⎯⎯→ c) C6H5CH2CH2OH + PCl5 ⎯⎯→ d) C6H5CH=CH2 + HCl, peroxide ⎯⎯→ e) C6H6 + CH3CH2Cl, AlCl3 ⎯⎯→ Answer: C Topic: Synthesis Sections: 11.9 and 15.6 Difficulty Level: Medium

36) Which of the following reactions would produce cumene? Cl

Benzene

a) Benzene

b)

AlCl3 HF OH

Benzene H2SO4

c)

Br

Benzene

AlCl3 d) e) All of these choices. Answer: E 15

Topic: Synthesis Section: 15.6 Difficulty Level: Hard

37) Which of the following reactions would yield cumene as the major product?

Benzene a)

CH3CH

CH2

H2SO4 CH3CHCH3

Benzene

b)

OH

H2SO4 CH3CHCH3

Benzene

c)

Benzene

Cl

AlCl3 CH3CH2CH2Cl

AlCl3 d) e) All of these choices. Answer: E Topic: Synthesis Section: 15.6 Difficulty Level: Hard

38) Which of the following reactions would give the product(s) indicated in substantial amounts (i.e., in greater than 50% yield)? NH2

NH2

+ CH3Cl

I

AlCl3

NH2

and

CH3

CH3 NH2

II

NH2

+ CH3Cl

AlCl3 CH3

III

+ CH3CH2CH2Cl

CH2CH2CH3

AlCl3

16

a) I b) II c) III d) All of these choices. e) None of these choices. Answer: E Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Easy

39) What would you expect to be the major product obtained from the following reaction? O

excess HN

AlCl3

?

CH3Cl

O

O

O

HN

HN

HN

I

II

III

O

O

HN

HN

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Medium

40) What would you expect to be the major product obtained from the following reaction? 17

O2N

O

AlCl3

+

O2 N O

I

II O2N

O

O2N

O2N O

?

Cl

III

O2 N

IV

V

O

O

a) I b) II c) III d) IV e) V Answer: A Topic: Reaction Products Section: 15.7 and 15.8 Difficulty Level: Medium

41) The major product(s) of the following reaction,

18

O O

AlCl3

+

?

Cl

O O

O O

O

O

I O

II

III O

IV

O

V O

would be: a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.7 and 15.8 Difficulty Level: Medium

42) What might be predicted to happen when the following substance undergoes Friedel-Crafts acylation? O2N

CH2

A

B

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 these choices. No reaction will occur. Answer: A Topic: Reaction Products

19

Section: 15.7 and 15.8 Difficulty Level: Medium

43) What would be the product of the following reaction sequence? OH i) SOCl2 ? ii) C6H6, AlCl3 O iii) Zn(Hg), HCl, heat O

O

OH OH

II

I

IV

III

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

44) What would be the product of the following reaction sequence?

20

OH

i) SOCl 2 ii) C6H6, AlCl3 iii) H2NNH2/KOH

O

?

O

O

OH OH

II

I

III

V

IV a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

45) What would be the product of the following reaction sequence? OH O

i) PCl5 ii) C6H6, AlCl3 iii) Zn(Hg), HCl, heat

O

?

OH

O OH

I

II

IV

III

V

a) I

21

b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

46) What would be the product of the following reaction sequence?

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

47) What would be the product of the following reaction sequence?

22

OH

O

i) SOCl2 ii) C6H6, AlCl3 iii) Zn(Hg), HCl, heat

?

O

OH

II

I

III O

OH

IV

V

a) I b) II c) III d) IV e) V Answer: B Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

48) What would be the product of the following reaction sequence?

23

a) I b) II c) III d) IV e) V Answer: B Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

49) Which would be the product of the following reaction sequence? O i) SOCl2 ? OH ii) benzene, AlCl3 iii) Zn(Hg), HCl

SO2

CO2

CH2

I

II

III

O

IV

V

24

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

50) Which would be the product of the following reaction sequence?

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

51) Which would be the product of the following reaction sequence?

25

O OH

i) PCl5 ii) benzene, AlCl3 iii) Zn(Hg), HCl

?

SO2

CO2

CH2

I

II

III

O

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

52) Which would be the product of the following reaction sequence?

a) I b) II c) III d) IV 26

e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

53) Which would be the product, X, of the following reaction sequence? O

O

Ph O Ph

i) benzene, AlCl3 ii) Zn(Hg), HCl

X

OH

+

O

SO2

CO2

CH2

I

II

III

O

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

54) Which would be the product, X, of the following reaction sequence?

27

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.7 and 15.9 Difficulty Level: Medium

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

28

O C CH2

Br

Br2

D

FeBr3

O

O

C CH2

C CH2 Br

I

II

O

O

C CH2

C CH2

Br

Br

III

IV

would be: a) I b) II c) III d) IV e) Approximately equal amounts of I and II. Answer: D Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

56) The major product, D, of the following reaction,

29

O H2SO4

D

SO3

O

O

HO3S

II

I SO3H

SO3H

O

O

SO3H IV III O

SO3H

V

would be: a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

57) What would you expect to be the major product obtained from the following reaction?

30

COOH SO3H COOH Br

Br2

?

FeBr3

COOH

COOH

COOH Br

SO3H

SO3H

Br

SO3H

SO3H

Br

I

II

III

IV

a) I b) II c) III d) IV e) Equal amounts of II and IV. Answer: C Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

58) What would you expect to be the major product obtained from the following reaction? NO2

Br2

NO2

?

FeBr3

SO3H NO2

NO2

NO2

Br

Br

SO3H

SO3H

Br

SO3H

SO3H

Br

I

II

III

IV

a) I b) II c) III d) IV e) Equal amounts of II and IV. Answer: C Topic: Reaction Products Section: 15.3 and 15.10 31

Difficulty Level: Medium

59) What would you expect to be the major product obtained from the following reaction? O

Br2, FeBr3

?

O

O

O

O

Br O

O

O

Br Br

II

I

III Br

O

O

O Br

O

IV

V

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

60) What would you expect to be the major product obtained from the following reaction?

32

1 equiv. Br2 FeBr3

?

Br

Br

II

I

Br

III Br

Br

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

61) What would you expect to be the major product obtained from the following reaction?

33

1 equiv. Cl2 FeCl3

?

Cl

Cl

Cl

II

I

III Cl

Cl

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

62) What would you expect to be the major product obtained from the following reaction? O

Cl2, FeCl3

?

HN

Cl O

O

O

HN

HN

II

III

Cl HN Cl

I O

O

HN

HN

Cl

Cl

IV

V

34

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

63) What would you expect to be the major product obtained from the following reaction? 1 equivalent Br2 O

?

FeBr3

Br O

O

O

Br

I

III

II

Br O O Br

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium 35

Br

64) What would you expect to be the major product obtained from the monobromination of mdichlorobenzene? Cl

Cl

Cl Br Cl Cl

Br

Br

I

II

Cl

III

a) I b) II c) III d) Equal amounts of I and II. e) Equal amounts of I, II and III. Answer: B Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium

65) Which would be the major product(s) of the following reaction? H3CO

O

Br2, FeBr3

H3CO

H3CO

O

O

?

H3CO

O

Br Br

I

Br2Fe

II

III

a) I b) II c) III d) I and II in roughly equal amounts. e) I and III in roughly equal amounts. Answer: A Topic: Reaction Products Section: 15.3 and 15.10 Difficulty Level: Medium 36

66) What would you expect to be the major product obtained from the following reaction? O

HNO3 H2SO4, heat

HN

O O2N

HN

?

O

NO2 O

HN

HN

II

III

O2N

I O

O

HN

HN

IV

NO2

NO2

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

67) What would you expect to be the major product obtained from the following reaction?

37

O

HNO3 H2SO4, heat

O

O

?

O

O

O 2N O

O

O

O2 N

II

I

III NO2

O

O O O NO2

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

68) What would be the major product(s) of the following reaction? CO2H

HNO3 H2SO4, heat NO2

CO2H NO2 NO2

I

CO2H NO2 NO2

II

CO2H O2N

?

O2N

CO2H NO2

NO2

IV

III

a) I b) II c) III 38

NO2

d) IV e) Approximately equal amounts of II and IV. Answer: C Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

69) What would you expect to be the major product obtained from the following reaction?

1 equiv. HNO3 H2SO4, heat

?

O 2N

NO2

II

I

NO2

III NO2

O2N

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

70) What would you expect to be the major product obtained from the following reaction?

39

HNO3 H2SO4, heat

HN

?

O2N HN

HN

HN

NO2

O2N

II

I

III

NO2 HN HN NO2

IV

V

a) I b) II c) III d) IV e) V Answer: A Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

71) What would you expect to be the major product(s) obtained from the mononitration of mdichlorobenzene? Cl

Cl

Cl

NO2 Cl

I

Cl NO2

O2N

II

Cl

III

a) I b) II c) III d) Equal amounts of I and II. e) Equal amounts of I, II and III. Answer: B 40

Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

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

O

HNO3 H2SO4 , heat SO3H HO

HO

O

O

HO

HO

O

NO2 SO3H

I

?

O

O2N SO3H O2N NO2

II

SO3H

SO3H

IV

III

a) I b) II c) III d) IV e) Equal amounts of I and II. Answer: C Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

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

41

HNO3

O

D

H2SO4 O O2N

O

I

NO2

O

II NO2

O NO2

IV

III

would be: a) I b) II c) III d) IV e) Equal amounts of I and II. Answer: D Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

74) Which would be the major product(s) of the following reaction? HO

O

HNO3 H2SO4 HO

HO

O

O

?

HO

O

NO2 NO2

I

HO3S

II

III

a) I b) II c) III d) I and II in roughly equal amounts. 42

e) I and III in roughly equal amounts. Answer: A Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

75) Which would be the major product(s) of the following reaction? H3CO

O

HNO3 H2SO4

H3CO

H3CO

O

O

?

H3CO

O

NO2 NO2

I

HO3S

II

III

a) I b) II c) III d) I and II in roughly equal amounts. e) I and III in roughly equal amounts. Answer: A Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Medium

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

43

O

H2SO4

?

NO2 O

O

O

O HO3S

SO3H NO2

I

NO2 SO3H

HO3S

II

NO2

NO2

IV

III

a) I b) II c) III d) Equal amounts of I and IV. e) Equal amounts of II and IV. Answer: C Topic: Reaction Products Section: 15.5 and 15.10 Difficulty Level: Medium

77) What would be the major product(s) of the following reaction? O

H2SO4 NO2

?

SO3

O O

O

O

HO3S

SO3H

NO2

I

NO2 SO3H

II

HO3S

NO2

NO2

IV

III

a) I b) II c) III d) Equal amounts of I and IV. e) Equal amounts of II and IV. Answer: C 44

Topic: Reaction Products Section: 15.5 and 15.10 Difficulty Level: Medium

78) The major product(s), C, of the following reaction, Cl Cl

Cl

SO3 H2SO4

C

Cl

Cl

SO3H Cl

Cl SO3H

I

HO3S

II

Cl

III

would be: a) I b) II c) III d) Approximately equal amounts of I and II. e) Approximately equal amounts of I and III. Answer: B Topic: Reaction Products Section: 15.5 and 15.10 Difficulty Level: Medium

79) The major product(s), A, of the following reaction, Cl2, hν

CH3CH2

CH3CH2

A

400 - 600 oC

Cl

CH3CH2

ClCH2CH2

CH3CH Cl

Cl

I

II

III

IV

would be: 45

a) I b) II c) A mixture of I and II. d) III e) IV Answer: E Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

80) The major product(s) of the following reaction, excess Cl2

?

400o - 600oC

Cl

Cl

Cl

Cl Cl

Cl

Cl Cl

I

II

IV

III

a) I b) II c) A mixture of I and II. d) III e) IV Answer: A Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

81) The major product(s) of the following reaction,

46

excess NBS ? ROOR

Br Br

Br

Br

Br

Br

Br Br

I

II

IV

III

a) I b) II c) A mixture of I and II. d) III e) IV Answer: D Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

82) The major product(s), A, of the following reaction, NBS ? ROOR

Br Br

Br Br

I

II

III

would be: a) I b) II c) A mixture of I and II. 47

IV

d) III e) IV Answer: E Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

83) What would be the major product of the following reaction? Cl2

CH2CH2CH3

Cl

CH2CH2CH3

?

400 oC CH2CH2CH3

CHCH2CH3 Cl

Cl

I

II CH2CHCH3

III CH2CH2CH2Cl

Cl

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

84) What would be the major product of the following reaction?

48

NBS ? ROOR

Br Br

Br

I

Br

Br

III

II

V

IV

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

85) What would be the major product of the following reaction? excess NBS ? ROOR

Br Br

Br Br

Br

Br

Br

Br

I

III

II

Br

IV

Br

IV

49

a) I b) II c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

86) What would you expect to be the major product obtained from the following reaction?

Cl2

?

peroxides Cl

Cl

II

I

Cl

III Cl

Cl

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

87) What would you expect to be the major product obtained from the following reaction? 50

Cl2

?

light Cl

Cl

Cl

II

I

III Cl

Cl

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

88) What would be the major product of the following reaction? NBS, ROOR ? light Br Br Br

I

II

III

Br Br

IV

V

a) I b) II 51

c) III d) IV e) V Answer: C Topic: Reaction Products Section: 15.12 Difficulty Level: Medium

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

CCl3

CCl3 Br

CCl3

Br Cl

I

Br

II

III

IV

a) I b) II c) III d) IV e) A mixture of III and IV. Answer: B Topic: Reaction Products Section: 15.3 and 15.12 Difficulty Level: Medium

90) What would you expect to be the major product obtained from the following reaction?

52

O

HNO3 H2SO4, heat

N N

O2N

O

O

N

N N

?

NO2

O N

N

N

O 2N

II

I

III

O O N N

N

N

NO2

NO2

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Hard

91) What would you expect to be the major product obtained from the following reaction?

53

N=O Br2 FeBr3

N=O

N=O

N=O

Br

Br

Br I

II

III N-OBr Br

IV

a) I b) II c) III d) IV e) A mixture of II and III. Answer: E Topic: Reaction Products Section: 15.4 and 15.10 Difficulty Level: Hard

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

54

II

I

III

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Hard

93) The reaction of benzene with chloride produces principally which of these?

Cl

in the presence of anhydrous aluminum

II

I

IV

III

V

a) I b) II c) III 55

d) IV e) V Answer: D Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Hard

94) The reaction of benzene with chloride produces principally which of these?

in the presence of anhydrous aluminum

II

I

IV

III

V

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Hard

56

Cl

95) The reaction of benzene with produces principally which of these?

in the presence of anhydrous aluminum chloride

II

I

IV

III

V

a) I b) II c) III d) IV e) V Answer: A Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Hard

96) The reaction of benzene with produces principally which of these?

in the presence of anhydrous aluminum chloride

57

a) I b) II c) III d) IV e) V Answer: A Topic: Reaction Products Section: 15.6 and 15.8 Difficulty Level: Hard

97) 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?

58

CO2H Br

CO2H

CO2H NO2

Br

NO2

I

NO2

Br

II

III

Br

CH3 NO2

Br

NO2

CO2H

IV

V

a) I b) II c) III d) IV e) V Answer: A Topic: Reaction Products Section: 15.3, 15.4, 15.10, and 15.13 Difficulty Level: Hard

98) 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?

a) I b) II c) III d) IV 59

e) V Answer: D Topic: Reaction Products Section: 15.3, 15.4, 15.10, and 15.13 Difficulty Level: Hard

99) What product would result from the following series of reactions,

i) AlCl3 ii) N-Bromosuccinimide, peroxides iii) CH3ONa, CH3OH, heat iv) m-CPBA v) CH3MgBr vi) NH4Cl

Cl

+

?

Br HO HO

II

I

III HO

HO

IV

V

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction products Section: 15.6, 15.12, 15.13 Difficulty Level: Hard

100) What product would result from the following series of reactions,

60

i) HF ii) N-Bromosuccinimide, peroxides iii) CH3ONa, CH3OH, heat iv) m-CPBA v) CH3MgBr vi) NH4Cl

+

?

Br HO HO

II

I

III HO

HO

IV

V

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.6, 15.12, 15.13 Difficulty Level: Hard

101) What product would result from the following series of reactions,

61

i) BF3 ii) N-Bromosuccinimide, peroxides iii) CH3ONa, CH3OH, heat iv) m-CPBA v) CH3MgBr vi) NH4Cl

OH

+

?

Br HO HO

II

I

III HO

HO

IV

V

a) I b) II c) III d) IV e) V Answer: D Topic: Reaction Products Section: 15.6, 15.12, 15.13 Difficulty Level: Hard

102) 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) -C≡N e) -CO2H Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy 62

103) Which of the following is not a meta-directing substituent when present on the benzene ring? a) -N=O b) -NO2 c) -N(CH3)3+ d) -C≡N e) -CO2H Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

104) 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. Cl

COOH

Cl

NHCOCH3

O

CCH3

Cl NO2 OH

I

II

III

CH3

CH2CH3

IV

V

a) I b) II c) III d) IV e) V Answer: C Topic: Directing Effects Section: 15.14 Difficulty Level: Easy

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

63

HO

O HO

O HO

O

I

O

O

HO

OH

II

IV

III

V

a) I b) II c) III d) IV e) V Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

106) Which of the following is not an ortho-para director in electrophilic aromatic substitution? a) -CF3 b) -OCH3 c) -CH3 d) -F e) -NH2 Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

107) Which of the following is not an ortho-para director in electrophilic aromatic substitution? a) -CCl3 b) -OCH3 c) -CH3 d) -F e) -NH2 Answer: A

64

Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

108) Which of the following is not an ortho-para director in electrophilic aromatic substitution? a) -SO3H b) -OCH3 c) -CH3 d) -F e) -NH2 Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

109) Which of the following is not an ortho-para director in electrophilic aromatic substitution?

a) b) -OCH3 c) -CH3 d) -F e) -NH2 Answer: A Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

110) Which is the best prediction of the site(s) of substitution when 3-methylphenol is nitrated? a) C-2 b) C-4 c) C-5 d) C-6 e) C-4 and C-6 Answer: E

65

Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

111) (Trifluoromethyl)benzene, C6H5CF3, will a) 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. Answer: D Topic: Directing Effects Section: 15.10 Difficulty Level: Easy

112) 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. Answer: A Topic: Directing Effects Section: 15.10 and 15.11 Difficulty Level: Easy

113) Which of these compounds gives essentially a single product on electrophilic substitution of a third group? a) p-chlorotoluene b) m-ethylanisole c) 1-bromo-2-chlorobenzene d) m-xylene e) 3-hydroxybenzoic acid Answer: D

66

Topic: Directing Effects Section: 15.10 Difficulty Level: Medium

114) Arrange the following compounds in order of decreasing reactivity in electrophilic substitution: O

I

O

Br

II

III

NO2

IV

V

a) V > II > I > III > IV b) II > V > III > I > IV c) IV > I > III > V > II d) III > II > I > IV > V e) IV > V > II > I > III Answer: B Topic: Directing Effects Section: 15.10 Difficulty Level: Medium

115) 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 must possess 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. Answer: C Topic: Directing Effects Section: 15.11 Difficulty Level: Medium

116) The ortho/para product ratio is expected to be the smallest for the bromination of which of these? a) Toluene b) Isopropylbenzene c) Butylbenzene 67

d) sec-Butylbenzene e) tert-Butylbenzene Answer: E Topic: Directing Effects Section: 15.10 and 15.15 Difficulty Level: Medium

117) Which reagent(s) would you use to carry out the following transformation? isopropylbenzene ⎯⎯⎯→ 2- and 4-chloro-1-isopropylbenzene a) Cl2, light, and heat b) Cl2, FeCl3 c) SOCl2 d) C2H5Cl, AlCl3 e) HCl, peroxides Answer: B Topic: Reagents Section: 15.3 and 15.10 Difficulty Level: Medium

118) Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯→ 2- and 4-chloro-1-ethylbenzene a) Cl2, light, and heat b) Cl2, FeCl3 c) SOCl2 d) C2H5Cl, AlCl3 e) None of these choices. Answer: B Topic: Reagents Section: 15.3 and 15.10 Difficulty Level: Medium

119) Which reagent(s) would you use to carry out the following transformation? t-butylbenzene ⎯⎯⎯→ p-chloro substitution product a) Cl2, light, and heat 68

b) Cl2, FeCl3 c) SOCl2 d) C2H5Cl, AlCl3 e) HCl, peroxide Answer: B Topic: Reagents Section: 15.3 and 15.10 Difficulty Level: Medium

120) Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯⎯→ 1-chloro-1-phenylethane a) Cl2, light, or heat b) Cl2, FeCl3 c) SOCl2 d) C2H5Cl, AlCl3 e) HCl, O2 Answer: A Topic: Reagents Section: 15.12 Difficulty Level: Medium

121) Which reagent(s) would you use to synthesize 2- and 4-bromo-1-cyclopentylbenzene from cyclopentylbenzene? a) N-Bromosuccinimide (NBS), CCl4, light b) PBr3 c) Br2, FeBr3 d) CH3CH2Br, AlBr3 e) HBr, ROOR Answer: C Topic: Reagents Section: 15.3 and 15.10 Difficulty Level: Medium

122) Which reagent would you use to carry out the following transformation? tert-butylbenzene ⎯⎯⎯→ p-tert-butylbenzenesulfonic acid 69

+ o-tert-butylbenzenesulfonic acid a) HNO3/H2SO4 b) tert-C4H9Cl/AlCl3 c) H2SO3/peroxides d) SO3/H2SO4 e) SO2/H2SO3 Answer: D Topic: Reagents Section: 15.5 and 15.10 Difficulty Level: Medium

123) Which reagent(s) would you use to carry out the following transformation? toluene ⎯⎯⎯→ benzoic acid a) Br2, heat, and light b) Cl2, FeCl3 c) KMnO4, OH-, heat (then H3O+) d) HNO3/H2SO4 e) SO3/H2SO4 Answer: C Topic: Reagents Section: 15.13 Difficulty Level: Medium

124) Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯⎯⎯→ benzoic acid a) Cl2, light, and heat b) Cl2, FeCl3 c) KMnO4, OH-, heat (then H3O+) d) HNO3/H2SO4 e) SO3/H2SO4 Answer: C Topic: Reagents Section: 15.13 Difficulty Level: Medium 70

125) Which reagent(s) would you use to carry out the following transformation? cumene ⎯⎯⎯→ 2- and 4-chlorocumene a) Cl2, light, and heat b) Cl2, FeCl3 c) SOCl2 d) C2H5Cl, AlCl3 e) HCl, peroxides Answer: B Topic: Reagents Section: 15.3 and 15.10 Difficulty Level: Hard

126) Which reagent(s) would you use to carry out the following transformation? toluene ⎯⎯⎯→ benzyl bromide a) Br2, FeBr3 b) N-Bromosuccinimide, ROOR, hν c) HBr d) Br2/CCl4 e) NaBr, H2SO4 Answer: B Topic: Reagents Section: 15.12 Difficulty Level: Hard

127) 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,Fe 1) CH3CH2CCl , AlCl3 2) Br2, Fe 3) Zn(Hg), HCl c)

O

1) CH3CH2CCl , AlCl3

2) Zn(Hg), HCl

3) Br2, Fe

O d) e) (1) (CH3)2CHCl, AlCl3 (2) Br2,Fe

71

Answer: D Topic: Reagents Section: 15.14 Difficulty Level: Hard

128) 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,Fe 1) CH3CH2CCl , AlCl3 2) Br2, Fe 3) Zn(Hg), HCl O

c)

d) e) (1) (CH3)2CHCl, AlCl3 (2) Br2,Fe Answer: D Topic: Reagents Section: 15.14 Difficulty Level: Hard

129) Which of the following compounds would be most reactive toward electrophilic substitution? OH

CH3

I

II

Br

III

a) I b) II c) III d) IV e) V Answer: A Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy 72

CHO

NO2

IV

V

130) Which of the following compounds would be least reactive toward electrophilic substitution? OH

CH3

I

II

Br

III

CHO

NO2

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

131) Which of the following compounds would be most reactive to ring bromination? CH3

NO2

I

II

CF3

III

Cl

NH2

IV

V

a) I b) II c) III d) IV e) V Answer: E Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

132) Which of the following compounds would be least reactive toward electrophilic substitution?

73

O O

NO2

NH

NO2

I

II

IV

III

V

a) I b) II c) III d) IV e) V Answer: B Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

133) Which of the following compounds would be most reactive toward electrophilic substitution? O O NO2

NH

NH2

NO2

I

II

IV

III

V

a) I b) II c) III d) IV e) V Answer: E Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

134) Which of the following compounds would be most reactive toward ring nitration?

74

O

O O

I a) I b) II c) III d) IV e) V

II

CF3

III

OH

NH

IV

V

Answer: D Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

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

I

HO

O

II

NH2

III

OCH3

CH3

IV

V

a) I b) II c) III d) IV e) V Answer: B Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

136) Which of the following compounds would be most reactive toward ring bromination?

75

O O

HO

O

NH2

OCH3

O

O

O

II

I

IV

III

V

a) I b) II c) III d) IV e) V Answer: C Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

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

I

II

O

NH

III

OCH3

CH3

IV

V

a) I b) II c) III d) IV e) V Answer: B Topic: Relative Reactivities Section: 15.11 Difficulty Level: Easy

138) Which of the following compounds would you expect to be most reactive toward ring nitration? a) Benzene b) Toluene 76

c) m-Xylene d) p-Xylene e) Benzoic acid Answer: C Topic: Relative Reactivities Section: 15.11 Difficulty Level: Medium

139) Which of the following compounds would you expect to be most reactive toward ring nitration? a) Benzene b) Toluene c) m-Xylene d) o-Xylene e) Benzoic acid Answer: C Topic: Relative Reactivities Section: 15.11 Difficulty Level: Medium

140.)Which of the following structures would not be a contributor to the resonance hybrid of the benzyl cation? CH3

H H

+ I

CH3

+CH2

CH2

+

CH3

+

+ II

III

IV

a) I b) II c) III d) IV e) V Answer: A Topic: Non-EAS Relative Rates and Intermediates Section: 15.12 77

IV

Difficulty Level: Medium

141) Which of the following carbocations would be most stable? CH3

a) C6H5CH2CH2CHCH2 CH2

b) C6H5CH2CH2CHCH3 CH3 C6H5CH2CH2CCH3

c) CH3

d) C6H5CH2CHCHCH3 CH3

e) C6H5CHCH2CHCH3 Answer: E Topic: Non-EAS Relative Rates and Intermediates Section: 15.12 Difficulty Level: Medium

142) Which alkyl halide would be most reactive in an SN2 reaction? a) C6H5CH2CH2CH2Br C6H5CHCH2Br

b)

CH3 C6H5CH2CHCH3 Br

c) CH3

C6H5CCH2Br

d)

CH3 Br C6H5CCH3

e)

CH3

78

Answer: A Topic: Non-EAS Relative Rates and Intermediates Section: 15.15 Difficulty Level: Medium

143) Which alkyl halide would be most reactive in an SN1 reaction? a) C6H5CH2CH2CH2Br C6H5CH2CHCH3 Br CH3

b)

C6H5CH2CBr CH3

c) Br

C6H5CCH3

d)

CH3 CH3 C6H5CCH2Br

e)

CH3

Answer: D Topic: Non-EAS Relative Rates and Intermediates Section: 15.15 Difficulty Level: Medium

144) The rate of solvolysis in ethanol is least for which of these compounds? a) C6H5CH2Cl C6H5C(CH3)2 Cl b) c) (C6H5)2CHCl

C6H5CHCl CH3 d) e) (C6H5)3CCl

Answer: A 79

Topic: Non-EAS Relative Rates and Intermediates Section: 15.15 Difficulty Level: Medium

145) Which of these species is/are proposed as intermediate(s) in the mechanism for the Birch reduction? a) Radical b) Carbanion c) Radical anion d) Two of these choices. e) All of these choices. Answer: E Topic: Non-EAS Relative Rates and Intermediates Section: 15.16 Difficulty Level: Hard

146) Benzoic acid can be prepared by the oxidation of all of the following compounds except this one: a) C6H5CH=CH2 b) C6H5C≡CH c) C6H5COCH3 d) C6H5CH2CH2CH3 e) C6H5C(CH3)3 Answer: E Topic: Synthesis Section: 15.13 Difficulty Level: Easy

147) Benzoic acid can be prepared by the oxidation of which of the following compounds: a) C6H5CH=CH2 b) C6H5C≡CH c) C6H5COCH3 d) C6H5CH2CH2CH3 e) All of these choices.

80

Answer: E Topic: Synthesis Section: 15.13 Difficulty Level: Easy

148) Benzoic acid can be prepared by the oxidation of which of the following compounds: a) C6H5CH=CH2 b) C6H5C≡CH c) C6H5COCH3 d) C6H5CH(CH3)2 e) All of these choices. Answer: E Topic: Synthesis Section: 15.13 Difficulty Level: Easy

149) Which of these is a satisfactory synthesis of 1-bromo-2-phenylethane? a) C6H5CH2CH3 + Br2, Fe3+ ⎯⎯→ b) C6H5CH2CH3 + Br2, 400°C ⎯⎯→ c) C6H5CH2CH2OH + Br2, CCl4 ⎯⎯→ d) C6H5CH=CH2 + HBr, ROOR ⎯⎯→ e) C6H5CH2CH3 + NBS, ROOR ⎯⎯→ Answer: D Topic: Synthesis Section: 15.13 Difficulty Level: Medium

150) What reagent can effect the following transformation? Br

CO2H Br

?

Br

CO2H Br

CO2H

a) CO2; then H3O+ b) H3O+, heat c) Mg; then CO2; then H3O+ 81

d) H2O2, heat e) KMnO4, OH-, heat; then H3O+ Answer: E Topic: Synthesis Section: 15.13 Difficulty Level: Medium

151) A good synthesis of O (CH3)3C

CCH3

would be: O

Benzene

a)

CH3CCl

(CH3)3CCl

AlCl3

AlCl3 O

Benzene

b)

(CH3)3CCl

CH3CCl

AlCl3

AlCl3

O

Benzene

CH3CCl

(CH3)2C

CH2

AlCl3 HF c) d) More than one of these choices. e) None of these choices.

Answer: B Topic: Synthesis Section: 15.14 Difficulty Level: Medium

152) Which would be a good synthesis of m-nitrobenzoic acid? Benzene

a)

HNO3/H2SO4

CH3Cl

1. KMnO4, NaOH, heat

heat

AlCl3

2. H3O+

82

Toluene

b) Toluene

1. KMnO4, NaOH, heat

HNO3/H2SO4

2. H3O+

heat

1. KMnO4, NaOH, heat

HNO3/H2SO4

2. H3O+ c) d) More than one of these choices. e) None of these choices.

heat

Answer: C Topic: Synthesis Section: 15.14 Difficulty Level: Medium

153) Which of the following would be the best synthesis of 1,4-dimethyl-2-nitrobenzene? Benzene

a) Toluene

b) p-Xylene

HNO3 H2SO4 HNO3

product

2 CH3Cl 2 AlCl3

product

H2SO4 HNO3

CH3Cl AlCl3

H2SO4 CH3Cl m-Nitrotoluene AlCl3 d) e) All of these choices are equally good.

c)

Answer: C Topic: Nomenclature, Synthesis Section: 15.14 Difficulty Level: Hard

154) 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. 83

d) HNO3/H2SO4; then KMnO4/-OH/heat, followed by H3O+; then CH3Cl/AlCl3. e) HNO3/H2SO4; then CO2, followed by H3O+. Answer: B Topic: Synthesis Section: 15.14 Difficulty Level: Hard

155) 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+. Answer: C Topic: Synthesis Section: 15.14 Difficulty Level: Hard

156) How might the following synthesis be carried out: CH2CH3

Benzene C 6 H6

a) C 6 H6

b)

several

?

steps CH3CH2Cl AlCl3 Cl2 FeCl3

Cl

Cl2 FeCl3 CH3CH2Cl AlCl3

product product

O

C6H6

c)

CH3CCl

Cl2

Zn(Hg)

AlCl3

FeCl3

HCl

CH3CCl

Zn(Hg)

Cl2

AlCl3

HCl

FeCl3

product

O

C6H6

d)

84

product

e) None of these syntheses is satisfactory. Answer: C Topic: Synthesis Section: 15.14 Difficulty Level: Hard

157) How might the following synthesis be carried out: CH2CH3

Benzene C 6 H6

a) C 6 H6

b)

several

?

steps CH3CH2Cl

Cl

Cl2 FeCl3 CH3CH2Cl

AlCl3 Cl2 FeCl3

AlCl3

product product

O

C6H6 c)

CH3CCl

Cl2

H2NNH2

AlCl3

FeCl3

KOH

product

O

C6H6

CH3CCl

Zn(Hg)

Cl2

AlCl3

HCl

FeCl3

d) e) None of these syntheses is satisfactory. Answer: C Topic: Synthesis Section: 15.14 Difficulty Level: Hard

158) How might the following synthesis be carried out: several steps Cl

85

product

C 6 H6

a) C 6 H6

b)

CH3CH2Cl

Cl2

AlCl3 Cl2

FeCl3 CH3CH2Cl

FeCl3

AlCl3

product product

O

C6H6

c)

CH3CCl

Cl2

Zn(Hg)

AlCl3

FeCl3

HCl

CH3CCl

Zn(Hg)

Cl2

AlCl3

HCl

FeCl3

product

O

C6H6

d) e) None of these syntheses is satisfactory.

product

Answer: D Topic: Synthesis Section: 15.14 Difficulty Level: Hard

159) How might the following synthesis be carried out: several steps Cl

C 6 H6

a) C 6 H6

b)

CH3CH2Cl AlCl3 Cl2 FeCl3

Cl2 FeCl3 CH3CH2Cl AlCl3

product product

O

C6H6

c)

CH3CCl

Cl2

Zn(Hg)

AlCl3

FeCl3

HCl

product

O

C6H6

CH3CCl

H2NNH2

Cl2

KOH

FeCl3

product

AlCl3 d) e) None of these syntheses is satisfactory.

86

Answer: D Topic: Synthesis Section: 15.14 Difficulty Level: Hard

160) How might the following synthesis be carried out: several steps Cl

C 6 H6

a) C 6 H6

b)

CH3CH2Cl

Cl2

AlCl3 Cl2

FeCl3 CH3CH2Cl

FeCl3

AlCl3

product product

O

C6H6 c)

CH3CCl

Cl2

H2NNH2

AlCl3

FeCl3

KOH

product

O

C6H6

H2NNH2

CH3CCl

Cl2 product

KOH FeCl3 AlCl3 d) e) None of these syntheses is satisfactory. Answer: D Topic: Synthesis Section: 15.14 Difficulty Level: Hard

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

ethylbenzene a)

NBS, hν

Br2

KOH

CCl4

Fe

CH3CH2OH

87

product

ethylbenzene

Br2

NBS, hν

KOH

Fe

CCl4

CH3CH2OH

b)

ethylbenzene

NBS, hν

KOH

Br2

CCl4 ZnO

CH3CH2OH c) Br2 product ethylbenzene Fe 630 oC d) e) None of these syntheses is satisfactory.

product product

Fe

Answer: B Topic: Synthesis Section: 15.14 Difficulty Level: Hard

162) Which is the best sequence of reactions for the following transformation? O

NO2

a) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H3O+, heat b) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat d) i) HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heat e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis Section: 15.14 Difficulty Level: Hard

163) Which is the best sequence of reactions for the following transformation? O OH

NO2

a) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H2O, NH4Cl 88

b) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat d) i) HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heat e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis Section: 15.14 Difficulty Level: Hard

164) Which is the best sequence of reactions for the following transformation? O

OH

H

NO2

a) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H2O, NH4Cl b) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat d) i) HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heat e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis Section: 15.14 Difficulty Level: Hard

165) Which is the best sequence of reactions for the following transformation? O

H

NO2

a) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H3O+, heat b) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat d) i)HNO3, H2SO4; ii) LiAlH4, H2O; iii) H3O+, heat 89

e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis Section: 15.14 Difficulty Level: Hard

166) Which is the best sequence of reactions for the following transformation? OH

O OCH3 NO2

a) i) HNO3, H2SO4; ii) 2EtMgBr, Et2O; iii) NH4Cl b) i) 2EtMgBr, Et2O; ii) H3O+; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) 2EtMgBr, Et2O d) i) LAH; ii) 2EtLi, Et2O; iii) HNO3, H2SO4, heat e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis Section: 15.14 Difficulty Level: Hard

167) Which is the best sequence of reactions for the following transformation? O

OCH3

+

NO2

NO2

a) i) HNO3, H2SO4; ii) 2EtMgBr, Et2O; iii) NH4Cl b) i) 2EtMgBr, Et2O; ii) H3O+; iii) HNO3, H2SO4 c) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) 2EtMgBr, Et2O d) i) LAH; ii) 2EtLi, Et2O; iii) HNO3, H2SO4, heat e) None of these syntheses is satisfactory. Answer: A Topic: Synthesis 90

Section: 15.14 Difficulty Level: Hard

168) Which is the best sequence of reactions for the following transformation? O OH NO2

a) i) SOCl2; ii) C6H6, AlCl3; iii) Zn(Hg),HCl; iv) HNO3, H2SO4 b) i) SOCl2; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) H2, Ni c) i) HNO3, H2SO4; ii) SOCl2; iii) C6H6, AlCl3; iv) Zn(Hg),HCl d) i) PBr3; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) NaBH4, H2O e) Two of these syntheses are satisfactory. Answer: C Topic: Synthesis Section: 15.14 Difficulty Level: Hard

169) What is the Birch reduction product of the following reaction?

Na, NH3(l) EtOH

I

II

III

?

V

IV

a) I b) II c) III d) IV e) V Answer: D Topic: Non-EAS Reactions Section: 15.16 Difficulty Level: Medium

91

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

would be: a) I b) II c) III d) IV e) V Answer: C Topic: Non-EAS Reactions Section: 15.16 Difficulty Level: Medium

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

92

would be: a) I b) II c) III d) IV e) V Answer: D Topic: Non-EAS Reactions Section: 15.16 Difficulty Level: Medium

172) The major product(s) of the following reaction,

93

would be: a) I b) II c) III d) IV e) V Answer: D Topic: Non-EAS Reactions Section: 15.16 Difficulty Level: Medium

173) The major product(s) of the following reaction,

94

would be: a) I b) II c) III d) IV e) V Answer: E Topic: Non-EAS Reactions Section: 15.15 Difficulty Level: Medium

174) SN1 solvolysis of C6H5CH=CHCH2Cl in water produces: a) C6H5CH2C(OH)=CH2 b) C6H5CH=CHCH2OH c) C6H5CHOHCH=CH2 d) A mixture of two of these choices. e) A mixture of all of these choices. Answer: D

95

Topic: Non-EAS Reactions Section: 15.15 Difficulty Level: Medium

175) Which compound is capable of undergoing both SN1 and SN2 reactions in ordinary nonacidic solvents? Br

Br

Br

Br Br

I

II

III

IV

V

a) I b) II c) III d) IV e) V Answer: D Topic: Non-EAS Reactions Section: 15.15 Difficulty Level: Medium

176) Which alkyl halide can undergo both SN1 and SN2 reactions in nonacidic solvents? a) CH3Br b) CH3CH2CH2Br CH2

CHCHCH3

Br c) d) C6H5CH2CH2CH2Br CH3 C6H5CCH2Br

e)

CH3

Answer: C Topic: Non-EAS Reactions Section: 15.15 Difficulty Level: Medium

96

Question type: fill-in-the-blank

177) 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 ___; and c) loss of a ___ to reform the aromatic system. Answer: electrophile; arenium ion; proton Topic: EAS Mechanism Section: 15.2 Difficulty Level: Easy

Question type: Molecular Drawing

178) Draw a mechanism that explains the formation of the following product in this FriedelCrafts alkylation: AlCl3

+ Cl

Answer: +

AlCl3

C H2

Cl

Cl

AlCl3

H

-H+

Topic: Mechanism, Carbocation Stability Section: 15.6 and 15.8 Difficulty Level: Hard

Question type: fill-in-the-blank 97

AlCl4-

179) When two different groups are present on a benzene ring, the ___ generally determines the outcome of an EAS reaction. Answer: more powerful activating group Topic: General EAS Reactivity Section: 15.14 Difficulty Level: Easy

180) Substituent groups affect both ___ and ___ in electrophilic aromatic substitution reactions. Answer: reactivity; orientation Topic: General EAS Reactivity Section: 15.10 Difficulty Level: Easy

181) 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. Answer: activating Topic: General EAS Reactivity Section: 15.10 Difficulty Level: Easy

182) 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. Answer: deactivating Topic: General EAS Reactivity Section: 15.10 Difficulty Level: Easy

183) With the exception of halogens, activating groups are ___ directors and deactivating groups are ___ directors. Answer: ortho/para; meta

98

Topic: General EAS Reactivity Section: 15.10 Difficulty Level: Easy

Question type: Essay

184) 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. O

Br2 FeBr3

HN O

?

Answer: 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 electronpoor. 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. Ring Ring A A O

O

HN O

+

Br

major products

HN O

Ring B

Br

Ring B

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

185) 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. E

3 E+ 2

or (-H+)

E O

O

1

Which substitution product forms preferentially and why? 99

O

Answer: 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. E+ E O

E

O

E

O H

O

H

H

-H+ E

O

H

H E

E+ O

O

E E

-H+ O

O

Topic: General EAS Reactivity Section: 15.2 and 15.11 Difficulty Level: Hard

186) 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. E

3 E+ 2 N H

or (-H+)

E N H

N H

1

Which substitution product forms preferentially and why? Answer: 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.

100

E+ E N H

N H

E N H

H

E N H

H

H

-H+ E

N H H

H E

E+ N H

E E

N H

-H+ N H

N H

Topic: General EAS Reactivity Section: 15.2 and 15.11 Difficulty Level: Hard

187) 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. E

3 E+ 2 S

or +

(-H )

E S

S

1

Which substitution product forms preferentially and why? Answer: 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.

101

E+ E S

E

S

E

S H

S

H

H

-H+ E

S

H

H E

E+ S

S

E E

-H+ S

S

Topic: General EAS Reactivity Section: 15.2 and 15.11 Difficulty Level: Hard

188) 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. E 4 3

E

E+ or

2 N 1

or

+

(-H ) E

N

N

N

Which substitution product(s) forms and why? Answer: 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.

102

H

H N

N

N

E+

H N

E

E

E

divalent, positively charged nitrogen poor resonance structure

H

H

E+

E

E

N

E

H

E+

H

E

N

N

N

H

H

E

E

N

N

N

N

divalent, positively charged nitrogen poor resonance structure

Topic: General EAS Reactivity Section: 15.2 and 15.11 Difficulty Level: Hard

189) 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. NO2

1 2

NO2

NO2+ or (-H+)

Which substitution product forms preferentially and why? Answer: 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.

103

H

H

NO2

NO2

NO2+

the existance of this "homobenzylic"resonance form contributes to the stability of this intermediate NO2

(-H+)

H NO2

NO2+ NO2

(-H+)

only one benzylic resonance form can be drawn

Topic: General EAS Reactivity Section: 15.2 and 15.11 Difficulty Level: Hard

190) 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. E 4

N 1

E

3

E+

2

(-H+)

instead of N

or N

E

N

Answer: 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.

104

H

E

‡

+

‡

+

H

N

N

E

Ea H

Ea

P.E.

E

+ N

Reaction Progress

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

191) 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. NO2

1 2

NO2

NO2+ instead of (-H+)

Answer: 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.

105

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

192) 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. E

3 E+ 2 O

instead of (-H+)

E O

O

1

Answer: 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

106

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

193) 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. E

3 E+ 2 N H

(-H+)

instead of E N H

N H

1

Answer: 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.

107

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

194) 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. E

3 E+ instead of 2 S

(-H+)

E S

S

Answer: 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.

108

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

195) 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. E

3 2

E+ (-H+)

N H

or

E N H

N H

1 indole

Which substitution product forms preferentially and why? Answer: 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. H

H

E

E N H

E

E

+

N H

N H

109

-H+

N H

E+

E

E N H

N H

E N H

N H

H

H

E

E N H

H

N H

H

H

-H+ E

N H

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

196) 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. E

3 E+

2

E

+

(-H )

O

or

O

O

1 benzo[b]furan

Which substitution product forms preferentially and why? Answer: 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. H

H

E

E+ O

E

E

O

O

110

+

-H

O

E+

E

E O

O

O

H

H

E

E

E

O

O

O H

H

H

-H+ O

E

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

197) 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. E

3 E+

2

E

+

(-H )

S

or

S

S

1 benzo[b]thiophene

Which substitution product forms preferentially and why? Answer: 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 H

H

E

E S

E

E

+

S

S

111

-H+

S

E+

E

E S

S

S

H

H

E

E

E

S

S

S H

H

H

-H+ S

E

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

198) 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). E

3 2 S

E+ E

instead of

(-H+) S

S

1 benzo[b]thiophene

Answer: 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.

112

‡ ‡ E S H

Ea H

Ea

P.E.

E

S

Reaction Progress

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

199) 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). E

3 2 O

E+

E

instead of

+

(-H )

O O

1 benzo[b]furan

Answer: 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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‡ ‡ E O H

Ea H

Ea

P.E.

E

O

Reaction Progress

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

200) 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). E

3 2 N H

E+

E

instead of +

(-H ) N H

1

N H

indole

Answer: 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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‡ ‡ E N H

Ea

H H

P.E.

Ea E

N H

Reaction Progress

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

201) 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. Answer: 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 1phenyl-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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H 2O

H

+

H 3 O+

+

H

+

2o, benzylic: stabilized by resonance,formed

2o, but not benzylic: less stable, not formed to any

almost exclusively

appreciable degree

OH

H

+

H chief product

OH not detected

Topic: Mechanism, Carbocation Stability Section: 15.12 Difficulty Level: Hard

202) 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. Answer: Reaction with Cl2/FeCl3 results in electrophilic aromatic substitution at the o- and ppositions, 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 freeradical halogenation via the benzyl radical intermediate. Cl2 FeCl3

Cl Cl

+ Cl

Cl2 heat

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

203) Suggest a reasonable synthetic strategy for the synthesis of 3,5-dinitrobenzyl alcohol from benzaldehyde.

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O

NO2

HNO3 (excess) H2SO4 O2N heat

O

Answer: benzaldehyde

NaBH4 H 2O

NO2 OH

O2N

3,5-dinitrobenzyl alcohol

Topic: Synthetic Strategy Section: 15.14 Difficulty Level: Medium

204) Suggest a reasonable synthetic strategy for the synthesis of 4-methyl-1-phenyl-1-pentanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COCl O

OH

NaBH4 H 2O

Cl O

AlCl3

Answer: 4-methylpentanoyl chloride

4-methyl-1-phenyl-1-pentanol

Topic: Synthetic Strategy Section: 15.7 Difficulty Level: Medium

205) Suggest a reasonable synthetic strategy for the synthesis of 6-methyl-3-phenyl-3-heptanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COCl O

O

OH

i) C2H 5MgBr ii) NH 4Cl

Cl

AlCl3

Answer: 4-methylpentanoyl chloride

6-methyl-3-phenyl-3-heptanol

Topic: Synthetic Strategy Section: 15.14 Difficulty Level: Hard

206) What product would result from the following series of reactions,

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1. Br2, FeBr3 2. Mg, ether 3. ethylene oxide 4. H3O+ 5. PBr3 6. Mg, ether 7. O

?

8. H3O+, heat (-H2O 9. HF

Answer: O

Br2, FeBr3

OH

MgBr

Br

Mg, ether H3O+

PBr3

O Br

MgBr

HF

Mg, ether H 3O + (-H2O)

Topic: Synthetic Strategy Section: 15.14 Difficulty Level: Hard

207) Propose a reasonable synthesis of the following compound from benzene.

multi-step process

Answer:

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O

Br2, FeBr3

OH

MgBr

Br

Mg, ether H3O+

PBr3

O Br

MgBr

HF

Mg, ether H 3O + (-H2O)

Topic: Synthetic Strategy Section: 15.14 Difficulty Level: Hard

208) What product would result from the following series of reactions: O

1. AlCl3 2. SOCl2 O

?

+ 3. AlCl3

O

Answer: O O

SOCl2

AlCl3 O

+ COOH

O

O

O

AlCl3

COCl O

Topic: Synthetic Strategy Section: 15.14 Difficulty Level: Hard

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