Chemistry Chapter 6 Which The Nucleophiles Below Would You Choose

Page 1

1.

Which of the following would you expect to have the highest boiling point?

A)

CH3CH2CH2Br

B)

CH3CH2CH2I

C)

CH3CH2CH2Cl

D)

CH3CH2CH2F

E)

CH3CH2CH3

2.

What would be the name of the following?

CH3CH2CHBrCHBrCH(CH 3)2

A)

3,4-dibromo-2-methylhexane

B)

1,2-dibromo-1-isopropylbutane

C)

2,3-dibromohexane

D)

3,4-dibromo-5-methylhexane

E)

3,4-dibromo-3-methylhexane

3.

What would be the major product of the following reaction?

H3C

CH3CH2

Br

HNa+ –CN

DMSO ?

A)

H3C

CH3CH2

CN

H

B)

H3C

CH3CH2

N

H

C

C)

H3C

CH3CH2

H

CN

D)

H3C

CH3CH2

H

N C

E)

H3C

CH3CH

H

Page 2

4.

Which of the following would you expect to react fastest with the nucleophile I–

(iodide)?

A)

CH3CH2CH2Br

B)

CH3CH2CH2Cl

C)

(CH3)2CHCH2Br

D)

(CH3)2CHCH2Cl

E)

(CH3)3CCH2Br

5.

Complete the following reaction:

CH3

P

CH3

H3C

CH2Br

+?

:

A)

CH3

PH3CBr CH 2CH3

+

B)

CH3

P

CH3

H3C

CH2

H

Br–

++

C)

CH3

P

CH3

H3CCH2

Br–

+

D)

CH3

P

CH2

H3C

CH3

+ + HBr

E)

no reaction will occur

6.

Which of the following would you expect to have the weakest C-X bond?

A)

CH3Cl

B)

CH3CH2Br

C)

CH3F

D)

CH3CH2I

E)

(CH3)2CHBr

Page 3

7.

Which of the following haloalkanes would not undergo the reaction below?

R–X + CH3S– CH3SR + X –

A)

(CH3)2CHI

B)

CH3Cl

C)

(CH3)3CBr

D)

CH3CH2Br

E)

CH3CH2CH2I

8.

Predict the major product of the following reaction:

H

Me

OTs

Et

?

NaCN

-OTs = -O3SC6H4CH3

A)

Et Me

CN

H

B)

Et Me

HCN

C)

NC H

D)

HCN

E)

Et Me

TsO CN

Page 4

9.

Predict the major product of the following reaction:

Ph

I

H

KN3?

A)

Ph

N3

H

B)

Ph

H

N3

C)

H

Ph

N3

D)

N3

Ph H

E)

no reaction occurs

10.

What is the major product of the following two-step reaction?

OH 1) TsCl, pyridine

2) NaCN ?

A)

ONa

B)

CN

C)

OTs

D)

O

E)

no reaction occurs

Page 5

11.

What is the major product of the following reaction:

Br Ph3P / DMSO ?

A)

PPh3Br

+–

B)

C)

P

Br

D)

E)

no reaction occurs

12.

Indicate the reagents required to achieve the following transformation:

HCH3

Br

CH3

CH3O H HCH3

CN

CH3

CH3O H

?

A)

NaCN

B)

1) NaF

2) KCN

C)

1) NaI

2) NaCN

D)

1) NaOMe

2) HCN / light

E)

None of the above.

Page 6

13.

What reactants are required to achieve the following transformation?

CN

?

A)

1. PBr3

2. NaCN

B)

C)

1. Br2, h

2. HCN

D)

1. SOCl2

2. KCN

E)

1. Br2, h

2. KCN

14.

What reactants are required to achieve the following transformation?

OH CN

?

A)

NaCN

B)

1) NaOH

2) KCN

C)

1.

2. KCN

Cl S

O

CH3

, pyridine

D)

1) Br2 / light

2) NaCN

E)

None of the above.

Page 7

15.

To which side (if any) would the following equilibrium lie?

CH3CH2S– K+ + HOH CH

3CH2SH + KOH

A)

to the left

B)

to the right

C)

equally to the right and left

D)

there is no way to tell

E)

only SN2, SN1 and E2 reactions are possible

16.

Several alkyl halides, including iodomethane, are known carcinogens or cancer-suspect

materials. To destroy these materials by conversion to non-electrophilic species, you

can react them with nucleophiles. Which of the following would be the best for rapidly

destroying methyl iodide (iodomethane)?

A)

CH3OH

B)

NH3

C)

H2O

D)

NaI

E)

CH3CO2H

17.

Which of the following is not normally a good leaving group on carbon?

A)

Br

B)

OCH3

C)

Cl

D)

OSO2R

E)

I

Page 8

18.

Predict the major product of the following reaction:

Br NaN3?

A)

N3

B)

C)

D)

E)

no reaction occurs

19.

Which of the following reagents would best accomplish a typical SN2 reaction?

A)

CH3OH

B)

H2O

C)

HCN

D)

KCN

E)

KOtBu

Page 9

20.

What would be the organic product of the following reaction?

C

CH3

D

HBr

CH3CO2– K++ ? + KBr

A)

C

CH3

D

OH

C

O

H3C

B)

C

D

H3C

OH

C

O

H3C

C)

CCH3

D

O HC

O

H3C

(racemic)

D)

All of the above.

E)

None of the above.

21.

SN2 substitution at secondary halides and sulfonates is often complicated by competing

E2 elimination. Which of the nucleophiles below would you choose to obtain the

highest yield in an SN2 reaction with menthyl bromide?

Br Nu

Nu

(SN2)

A)

CH3ONa

B)

CH3CO2Na

C)

(CH3)3N

D)

(CH3)3COK

E)

C6H5SNa

Page 10

22.

Arrange the following in order of increasing nucleophilicity.

NH2NH3OH H2ONH4

A)

NH4OH

H2ONH3NH2

B)

NH4OH NH2H2O NH3

C)

NH4

H2O

NH3

OH

NH2

D)

NH4H2ONH3OH

NH2

E)

NH4H2O NH3OH NH2

23.

Which of the haloalkanes shown below would react most rapidly with cyanide ion?

A)

A

B)

B

C)

C

D)

D

E)

E

24.

The Walden Inversion (inversion of configuration) is associated with which of the

following?

A)

E1 reaction

B)

free-radical halogenation

C)

SN1 reaction

D)

SN2 reaction

E)

None of the above.

Page 11

25.

Predict the major product of the following reaction:

Cl P(CH3)3

A)

P(CH3)3

Cl

B)

C)

Cl

HPCH3

+

D)

P(CH3)3

Cl

E)

None of the above.

26.

Which of the following can be used to synthesize (R)-2-cyanopentane from

(R)-2-bromopentane?

A)

NaBr

B)

NaCN

C)

NaI followed by KCN

D)

NaCN followed by HI

E)

this reaction cannot occur

27.

What is the correct stereochemistry of the product of the following reaction:

Cl

Br

excess NaCN

A)

3R,4S

B)

2S,3R

C)

2R,3S

D)

2R,3R

E)

3R,4R

Page 12

28.

Which of the following is the best leaving group?

A)

I

B)

NH2

C)

HO

D)

F

E)

CH3O

Page 13

29.

Predict the major product of the following reaction:

Cl

NaSCH3

A)

SCH3

B)

SCH3

C)

CH3

D)

SCH3

E)

no reaction will occur

Page 14

30.

If the reaction rate of the following reaction is x, doubling the concentration of KCN

would give what rate?

Cl +KCN

A)

2x

B)

x/2

C)

x2

D)

x2/2

E)

no change in reaction rate

31.

Name the following compound:

Cl

Br

A)

(1S, 2S, 5R)-1-bromo-2-isopropyl-5-chlorocyclohexane

B)

(1R, 2R, 5R)-1-bromo-2-isopropyl-5-chlorocyclohexane

C)

(1S, 3S, 4R)-1-chloro-3-bromo-4-isopropylcyclohexane

D)

(1S, 2S, 4R)-2-bromo-4-chloro-1-isopropylcyclohexane

E)

(1R, 2S, 4R)-2-bromo-4-chloro-1-isopropylcyclohexane

Page 15

32.

Predict the major product of the following reaction:

CH2CH3

H3C I

H

NaN3?

A)

CH2CH3

H3C N3

H

B)

CH2CH3

H3C I

N3

C)

CH2CH3

N3CH3

H

D)

N3

H CH2CH3

CH3

E)

None of the above.

33.

Which of the following statements best describes why I– is a better nucleophile than F–

in solution?

A)

F– is a stronger base than I–.

B)

Solvation of F– impedes its nucleophilicity compared to I–.

C)

I– is a stronger base than F–.

D)

Solvation of I– increases its nucleophilicity compared to that of F–.

E)

A and B both offer explanations as to why I– is a better nucleophile than F– in

solution.

Page 16

34.

The curved arrows below represent what type of reaction mechanism?

OH O

R

HO

R

O

A)

nucleophilic substitution

B)

dissociation

C)

nucleophilic addition

D)

electrophilic addition

E)

None of the above.

35.

For the following reaction what is the most likely product?

Br

NaSH

acetone

A)

SH

B)

SH

racemic mixture

C)

SH

D)

E)

no reaction

36.

Which of the following statements are true of an SN2 reaction.

A)

follow a first order rate law

B)

typically are stereoselective

C)

the fastest step is the rate-determining step

D)

the carbocation intermediate adopts a trigonal planar geometry

E)

all of the above

Page 17

37.

Which set of reagents will best accomplish the following reaction?

OH

Br

H

O

H

A)

NaBr, acetone

B)

H2SO4, H2O

C)

Br2, hv

D)

NaOEt, DMSO

E)

None of the above.

38.

What is the best way to prepare the compound below?

OCH3

A)

OH H2SO4, CH3OH

B)

OH 1) NaH

2) CH3I

C)

CH3OH

1) NaH

2) I

D)

CH3OH

H2SO4

OH

E)

None of the above.

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Answer Key