Essential Organic Chemistry 2nd Edition Bruice - Test Bank

Essential Organic Chemistry 2nd Edition Bruice – Test Bank

 

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Essential Organic Chemistry, 2e (Bruice)

 

Chapter 5

 

Reactions of Alkenes and Alkynes: An Introduction to Multistep Synthesis

 

1)

 

What is the role of the p  bond of an alkene in an electrophilic addition reaction?

 

Answer:

 

The relatively loosely held p electrons of the carbon-carbon double bond attack an electrophile to begin the reaction.

 

Section:

 

5.0

 

2)

 

Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

 

 

 

Answer:

 

 

 

 

Section:

 

5.1

 

3)

 

What is the product in the following reactions?

 

 

 

Answer:

 

 

 

 

Section:

 

5.1 and 5.3

4)

 

Which of the following is the most stable carbocation?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

D

 

Section:

 

5.2

 

5)

 

Which of the following alkenes reacts with HCl at the slowest rate?

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

A

 

Section:

 

5.2

 

6)

 

Which of the following compounds will react most rapidly with HCl?

 

1. A)

 

5-methyl-1-hexene

 

1. B)

 

4-methyl-1-hexene

 

1. C)

 

(E)-5-methyl-2-hexene

 

1. D)

 

(E)-2-methyl-3-hexene

 

1. E)

 

2-methyl-2-hexene

 

Answer:

 

E

 

Section:

 

5.2

 

7)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

8)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

9)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

10)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

11)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

12)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.3

 

13)

 

What is the major product in the following reaction?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

C

 

Section:

 

5.4

 

14)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.4

 

15)

 

Draw the major organic product generated in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.4

 

16)

 

Complete the following reaction and provide a detailed, step-by-step mechanism for the process.

 

 

 

Answer:

 

 

 

 

Section:

 

5.4

 

17)

 

What is the major product from the acid-catalyzed hydration of 2-methyl-2-pentene?

 

1. A)

 

2-methylpentane

 

1. B)

 

2-methyl-1-pentanol

 

1. C)

 

2-methyl-2-pentanol

 

1. D)

 

2-methyl-3-pentanol

 

1. E)

 

1-methoxypentane

 

Answer:

 

C

 

Section:

 

5.4

 

18)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.4

 

19)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.5

 

20)

 

What is/are the product(s) in the following reaction?

 

 

 

Answer:

 

 

 

 

Section:

 

5.5

 

21)

 

How many electrons are involved in a carbon-carbon triple bond?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

6

 

Answer:

 

E

 

Section:

 

5.6

 

22)

 

What is the general formula for a noncyclic alkyne?

 

1. A)

 

CnH2n+2

 

1. B)

 

CnH2n

 

1. C)

 

CnH2n-1

 

1. D)

 

CnH2n-2

 

1. E)

 

CnH2n-4

 

Answer:

 

D

 

Section:

 

5.6

 

23)

 

What is the IUPAC name for the following alkyne?

 

 

 

1. A)

 

5-Bromo-2-heptyne

 

1. B)

 

3-Bromo-5-heptyne

 

1. C)

 

2-Bromomethyl-4-hexyne

 

1. D)

 

5-Bromo-5,5-dimethylhexyne

 

1. E)

 

5-Bromo-5-methyl-2-hexyne

 

Answer:

 

E

 

Section:

 

5.7

 

24)

 

Write structures and give IUPAC names for all alkynes with the molecular formula of C5H8.

 

Answer:

 

 

 

 

Section:

 

5.7

 

25)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

2,5,5-trimethyl-3-heptyne

 

Section:

 

5.7

 

26)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

1-pentyne

 

Section:

 

5.7

 

27)

 

What is the IUPAC name for the structure shown below?

 

 

 

Answer:

 

1-bromo-3-hexyne

 

Section:

 

5.7

 

28)

 

Draw an acceptable structure for acetylene.

 

Answer:

 

HCCH

 

Section:

 

5.7

 

29)

 

Draw an acceptable structure for 3-sec-butyl-1-heptyne.

 

Answer:

 

 

 

 

Section:

 

5.7

 

30)

 

Draw an acceptable structure for 2-hexyne.

 

Answer:

 

 

 

 

Section:

 

5.7

 

31)

 

How many distinct terminal alkynes exist with a molecular formula of C5H8?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

5

 

Answer:

 

B

 

Section:

 

5.7

 

32)

 

How many distinct internal alkynes exist with a molecular formula of C6H10?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

4

 

1. E)

 

5

 

Answer:

 

C

 

Section:

 

5.7

 

33)

 

What is the common name for the following alkyne?

 

 

 

1. A)

 

Neohexyne

 

1. B)

 

Trimethylpropyne

 

1. C)

 

Trimethylacetylene

 

1. D)

 

tert-Butylacetylene

 

1. E)

 

Isopropylacetylene

 

Answer:

 

D

 

Section:

 

5.7

 

34)

 

Give the systematic name for the alkyne shown below.

 

 

 

Answer:

 

6,6,6-trichloro-2-hexyne

 

Section:

 

5.7

 

35)

 

Which of the following is a correct statement about the carbon-carbon triple bond in an alkyne?

 

1. A)

 

composed of one sigma bond and one pi bond

 

1. B)

 

composed of two sigma bonds and one pi bond

 

1. C)

 

composed of one sigma bond and two pi bonds

 

1. D)

 

composed of two sigma bond and two pi bond

 

1. E)

 

composed of one sigma bond, one pi bond and one delta bond

 

Answer:

 

C

 

Section:

 

5.8

 

36)

 

What is the hybridization of the carbon atoms numbered 1 and 2 respectively in the following structure?

 

 

 

1. A)

 

sp3, sp2

 

1. B)

 

sp2, sp2

 

1. C)

 

sp, sp

 

1. D)

 

sp2, sp

 

1. E)

 

sp, sp2

 

Answer:

 

D

 

Section:

 

5.8

 

37)

 

How many atoms are attached to an atoms having a sp hybridization?

 

1. A)

 

0

 

1. B)

 

1

 

1. C)

 

2

 

1. D)

 

3

 

1. E)

 

4

 

Answer:

 

C

 

Section:

 

5.8

 

38)

 

Which of the following statements is not true about propyne, HCCCH3?

 

1. A)

 

It contains six sigma bonds.

 

1. B)

 

It contains three pi bonds.

 

1. C)

 

The HCH bond angle is about 109.5°.

 

1. D)

 

The CCC bond angle is 180°.

 

1. E)

 

The pi bond is weaker than the sigma bond.

 

Answer:

 

B

 

Section:

 

5.8

 

39)

 

What two atomic orbitals or hybrid atomic orbitals overlap to form the carbon-carbon σ bond in ethyne?

 

1. A)

 

sp3sp3

 

1. B)

 

pp

 

1. C)

 

sp2sp2

 

1. D)

 

ss

 

1. E)

 

spsp

 

Answer:

 

E

 

Section:

 

5.8

 

40)

 

What are the hybridizations of the carbon atoms numbered 1 and 2 in the structure below?

 

1    2

H3C-CHCH-CC-H

 

1. A)

 

sp3, sp2

 

1. B)

 

sp2, sp2

 

1. C)

 

sp2, sp

 

1. D)

 

sp, sp

 

Answer:

 

D

 

Section:

 

5.8

 

41)

 

What is the hybridization of the carbon atom numbered 1 in the structure below?

 

 

 

1. A)

 

sp

 

1. B)

 

sp2

 

1. C)

 

sp3

 

1. D)

 

d2sp3

 

1. E)

 

sp-sp2

 

Answer:

 

A

 

Section:

 

5.8

 

42)

 

Which of the following improperly describes the physical properties of an alkyne?

 

1. A)

 

relatively nonpolar

 

1. B)

 

nearly insoluble in water

 

1. C)

 

less dense than water

 

1. D)

 

insoluble in most organic solvents

 

Answer:

 

D

 

Section:

 

5.9

 

43)

 

Which of the following are correct statements concerning unsaturated hydrocarbons?

 

1. A)

 

All unsaturated hydrocarbons are insoluble in water.

 

1. B)

 

All unsaturated hydrocarbons are soluble in nonpolar solvents.

 

1. C)

 

All unsaturated hydrocarbons are more dense than water.

 

1. D)

 

A and B

 

1. E)

 

A, B, and C

 

Answer:

 

D

 

Section:

 

5.9

 

44)

 

Although you might expect 1-propyne to be more reactive than 1-propene in electrophilic addition reactions, the reverse is true. Explain this using your knowledge of the mechanism of electrophilic additions to both alkynes and alkenes.

 

Answer:

 

When HCl is added to an alkene, a secondary carbocation intermediate is formed,  When HCl is added to an alkyne, a vinylic carbocation is formed as an intermediate,  Alkynes are less stable than alkenes but vinylic carbocations are less stable than secondary carbocations. Thus, alkenes are more reactive than alkynes since the difference in stabilities between the carbocations is greater than the difference in stabilities between the alkene and alkyne.

 

Section:

 

5.10

 

45)

 

Which of the following statements correctly describes the general reactivity of alkynes?

 

1. A)

 

An alkyne is an electron-rich molecule and therefore reacts as a nucleophile.

 

1. B)

 

The σ bonds of alkynes are higher in energy than the π bonds and are thus more

reactive.

 

1. C)

 

Unlike alkenes, alkynes fail to undergo electrophilic addition reactions.

 

1. D)

 

Alkynes are generally more reactive than alkenes.

 

1. E)

 

none of the above

 

Answer:

 

A

 

Section:

 

5.10

 

46)

 

Describe the role of the alkyne in the reaction between an alkyne and a hydrogen halide.

 

Answer:

 

An alkyne is an electron-rich molecule because of its two p bonds and thus an alkyne is a nucleophile. p electrons from the alkyne triple bond attack the electrophilic hydrogen of the hydrogen halide during the first step of the reaction between an alkyne and a hydrogen halide.

 

Section:

 

5.10

 

47)

 

What is the major product of the following reaction?

 

HCl

CH3CCH

 

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

CH3CHCHCl

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

B

 

Section:

 

5.10

 

48)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.10

 

49)

 

In the addition of hydrogen bromide to alkynes, which of the following species is believed to be an intermediate?

 

1. A)

 

vinyl anion

 

1. B)

 

vinyl cation

 

1. C)

 

vinyl radical

 

1. D)

 

carbene

 

1. E)

 

none of the above

 

Answer:

 

B

 

Section:

 

5.10

 

50)

 

Which of the following compounds is the major product when 1-hexyne is treated with excess HBr?

 

1. A)

 

1,1-dibromohexane

 

1. B)

 

1,1-dibromohexene

 

1. C)

 

1,2-dibromohexene

 

1. D)

 

1,2-dibromohexane

 

1. E)

 

2,2-dibromohexane

 

Answer:

 

E

 

Section:

 

5.10

 

51)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.10

 

52)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.10

 

53)

 

Which of the following are enol forms of 2-butanone?

 

 

 

1. A)

 

 

 

 

1. B)

 

 

 

 

1. C)

 

 

 

 

1. D)

 

 

 

 

1. E)

 

 

 

 

Answer:

 

E

 

Section:

 

5.11

 

54)

 

What is the term used for isomers that are in rapid equilibrium?

 

1. A)

 

functonality

 

1. B)

 

keto-enol tautomers

 

1. C)

 

constitutional isomers

 

1. D)

 

conformational isomers

 

1. E)

 

cis-trans isomers

 

Answer:

 

B

 

Section:

 

5.11

 

55)

 

Which of the following is the final and major product of this reaction?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

A

 

Section:

 

5.11

 

56)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.11

 

57)

 

Which of the alkyne addition reactions below involves an enol intermediate?

 

1. A)

 

hydroboration/oxidation

 

1. B)

 

treatment with HgSO4 in dilute H2SO4

 

1. C)

 

hydrogenation

 

1. D)

 

both A and B

 

1. E)

 

none of the above

 

Answer:

 

D

 

Section:

 

5.11

 

58)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.11

 

59)

 

Which of the following reagents gives the reaction shown below?

 

CH3CH=CH2     +     ?     →     CH3CH2CH3

 

1. A)

 

H2/HCl

 

1. B)

 

H2/H2SO4

 

1. C)

 

H2/Ni

 

1. D)

 

H2O/Ni

 

1. E)

 

H2O/H2SO4

 

Answer:

 

C

 

Section:

 

5.12

 

60)

 

Upon hydrogenation, which of the following alkenes releases the least heat per mole?

 

1. A)

 

3,4-dimethyl-1-hexene

 

1. B)

 

(Z)-3,4-dimethyl-2-hexene

 

1. C)

 

(E)-3,4-dimethyl-2-hexene

 

1. D)

 

(Z)-3,4-dimethyl-3-hexene

 

1. E)

 

(E)-3,4-dimethyl-3-hexene

 

Answer:

 

E

 

Section:

 

5.12

 

61)

 

The reagent needed to convert 2-butyne to cis-2-butene is:

 

1. A)

 

H2/Pt

 

1. B)

 

H2/Lindlar’s catalyst

 

1. C)

 

Li/NH3

 

1. D)

 

Na/NH3

 

1. E)

 

H+/Zinc dust

 

Answer:

 

B

 

Section:

 

5.12

 

62)

 

A mixture of 1-heptyne, 2-heptyne, and 3-heptyne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased. If one assumes that the hydrogenation went to completion, how many distinct seven-carbon hydrocarbons were produced?

 

1. A)

 

1

 

1. B)

 

2

 

1. C)

 

3

 

1. D)

 

6

 

1. E)

 

8

 

Answer:

 

A

 

Section:

 

5.12

 

63)

 

Provide the structure of the major organic product(s) in the reaction below.

 

 

 

Answer:

 

 

 

 

Section:

 

5.12

 

64)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.12

 

65)

 

Provide the structure of the major organic product in the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.12

 

66)

 

What is the product when 3-heptyne reacts with the Lindlar catalyst?

 

1. A)

 

2-methyl-2-heptene

 

1. B)

 

trans-3-heptene

 

1. C)

 

cis-2-methyl-3-hexene

 

1. D)

 

cis-3-hexene

 

1. E)

 

none of the above

 

Answer:

 

D

 

Section:

 

5.12

 

67)

 

Which is the correct order of decreasing acidity in the following compounds?

 

H2O           CH3CH3               NH3          CH2CH2            HCCH

A                    B                           C                       D                           E

 

1. A)

 

A > E > C > D > B

 

1. B)

 

A > E > D > B > C

 

1. C)

 

E > A > C > B > D

 

1. D)

 

A > C > E > D > B

 

1. E)

 

E > D > B > A > C

 

Answer:

 

A

 

Section:

 

5.13

 

68)

 

Explain why HCN is a stronger acid than HCCH.

 

Answer:

 

Because nitrogen is more electronegative than carbon.

 

Section:

 

5.13

 

69)

 

Which hydrogens are more acidic, those of benzene or those of cyclohexane? Why?

 

 

 

Answer:

 

Benzene. The carbon hybridization of benzene is sp2 while that of cyclohexane is sp3. The more s character in benzene causes its hydrogens to be more acidic than those of cyclohexane.

 

Section:

 

5.13

70)

 

Why are terminal alkynes more acidic than other hydrocarbons?

 

Answer:

 

The carbanion which results upon deprotonation of a terminal alkyne has the lone pair of electrons in an sp hybridized orbital. The greater % s character of this orbital gives the orbital a significantly lower energy.

 

Section:

 

5.13

 

71)

 

Which of the species below is less basic than acetylide,  ?

 

1. A)

 

CH3Li

 

1. B)

 

CH3ONa

 

1. C)

 

NaOH

 

1. D)

 

both B and C

 

1. E)

 

all of the above

 

Answer:

 

D

 

Section:

 

5.13

 

72)

 

Among the compounds water, 1-butyne, 2-butyne, and ethane, which are stronger acids than ammonia?

 

1. A)

 

1-butyne and ethane

 

1. B)

 

water and 1-butyne

 

1. C)

 

water and ethane

 

1. D)

 

1-butyne and 2-butyne

 

Answer:

 

B

 

Section:

 

5.13

 

73)

 

What type of organic product results when 1-butyne is treated with 6M aqueous NaOH?

 

1. A)

 

a sodium acetylide

 

1. B)

 

an enol

 

1. C)

 

an alcohol

 

1. D)

 

an aldehyde

 

1. E)

 

Not much reaction; most of the alkyne remains unchanged.

 

Answer:

 

E

 

Section:

 

5.13

 

74)

 

Provide the structure of the major organic product of the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.13

75)

 

Provide the structure of the major organic product(s) in the reaction below.

 

CH3CH2CH

 

Answer:

 

CH3CH2CCCH2Ph

 

Section:

 

5.14

 

76)

 

Provide the structure of the major organic product of the following reaction.

 

 

 

Answer:

 

 

 

 

Section:

 

5.14

 

77)

 

Suggest a plausible scheme for the following synthesis:

 

 

 

Answer:

 

 

 

 

Section:

 

5.15

 

78)

 

Describe a sequence of reactions by which 3-heptyne can be straightforwardly prepared from acetylene.

 

Answer:

 

1)     NaNH2

2)     CH3CH2Br

3)     NaNH2

4)     CH3CH2CH2Br

 

Section:

 

5.15

 

79)

 

Describe a sequence of reactions by which     can be straightforwardly prepared from 1-butyne.

 

Answer:

 

1)    NaNH2

2)    CH3CH2Br

3)    HgSO4, H2O, H2SO4

 

Section:

 

5.15

 

80)

 

Describe a sequence of reactions by which cis-2-pentene could be prepared from acetylene.

 

Answer:

 

1)     NaNH2

2)     CH3CH2Br

3)     NaNH2

4)     CH3Br

5)     H2, Lindlar’s catalyst

 

Section:

 

5.15

 

81)

 

What is/are the major organic product(s) of the following reaction?

 

 

 

1. A)

 

CH2CH2 + HCCH

 

1. B)

 

CH3CH2CCH

 

1. C)

 

HCCBr

 

1. D)

 

HCCCH2CH2Br

 

1. E)

 

CH3CCCH3

 

Answer:

 

B

 

Section:

 

5.15

 

82)

 

What is the structure of the monomer from which the following polymer is made?

 

 

 

1. A)

 

CH3CH3

 

1. B)

 

CH2CH2

 

1. C)

 

CH3CHCH2

 

1. D)

 

CH2CHCHCH2

 

1. E)

 

CH3CHCHCH3

 

Answer:

 

E

 

Section:

 

5.16

 

83)

 

What is the structure of the monomer from which the following polymer is made?

 

 

 

1. A)

 

I

 

1. B)

 

II

 

1. C)

 

III

 

1. D)

 

IV

 

1. E)

 

V

 

Answer:

 

B

 

Section:

 

5.16

 

84)

 

Which of the following addition polymers results from the reaction below?

nCF2CF2  ?

 

 

1. A)

 

[CF-CF]n

 

1. B)

 

[CF3-CF3]n

 

1. C)

 

[-CF2-CHCHCF2-]n

 

1. D)

 

[-CF2-CF2-]n

 

1. E)

 

[-CF2CF2-]n

 

Answer:

 

D

 

Section:

 

5.16

 

85)

 

Which of the following species can best serve as a radical initiator for radical polymerization?

 

1. A)

 

ROH

 

1. B)

 

ROR

 

1. C)

 

ROOR

 

1. D)

 

RCOOR

 

1. E)

 

RCOOH

 

Answer:

 

C

 

Section:

 

5.16

 

86)

 

Which of the following is the first chain propagating step in the radical polymerization of ethylene using a peroxide initiator?

 

 

1. A)

 

ROOR + CH2CH2 → ROCH2CH2OR

 

 

1. B)

 

∙

RO∙ + CH2CH2 → ROCH2CH2

 

 

1. C)

 

RO∙ + CH2CH2 → ROCHCH2 + H∙

 

 

1. D)

 

∙         ∙

ROOR + CH2CH2 → 2 ROH + CHCH

 

 

1. E)

 

∙        ∙

2RO∙ + CH2CH2 → 2 ROH + CHCH

 

Answer:

 

B

 

Section:

 

5.16

 

87)

 

List the three phases in the mechanism of chain-growth polymerization.

 

Answer:

 

1. Initiation
2. Propagation
3. Termination

 

Section:

 

1.2

 

88)

 

Show the mechanism for the formation of a segment of polystyrene containing two molecules of styrene and initiated by hydrogen peroxide.

 

Answer:

 

 

 

 

Section:

 

5.16

 

89)

 

Provide a mechanism to show how H2CC(CH3)2 is polymerized using BF3 as the initiatior.

 

Answer:

 

 

 

 

Section:

 

5.16