Test Bank for Organic Chemistry 1st Edition by Klein · PDF fileTest Bank for Organic...

Test Bank for Organic Chemistry 1st Edition by Klein

Chapter 7

Topic: Introduction to Substitution

Section 1

Difficulty Level: Easy

1. Which of the following is a substitution reaction?

Ans: C

Chapter 7


Section 1



Ans: D

Chapter 7


Section 1



Ans: B


Section 1

Difficulty Level: Medium

5. Draw an example of a substitution reaction.

Ans: Numerous options!


Section 1


6. What is the nucleophile in the following reaction?

Ans: B


Section 1


7. What is the electrophile in the following reaction?

Ans: A


Section 1


8. What is the leaving group in the following reaction?

carbon bromide

hydrogen

nitrogen

Ans: B


Section 1

Difficulty Level: Hard

9. What are two features typical of a leaving group?

Ans: 1. A leaving group withdraws electron density from the adjacent carbon, and 2. A leaving group can stabilize negative charge.


Section 1


10. For the following reaction, label the nucleophile, electrophile, and leaving group.

Ans:


Section 1


11. What is the nucleophile in the following reaction?

Ans: A


Section 1


12. What is the electrophile in the following reaction?

Ans: B


Section 1


13. What is the leaving group in the following reaction?

Sulfur

Carbon

Hydrogen

Iodide

Ans: D

Topic: Alkyl Halides

Section 2


14. Which of the following is the correct IUPAC name of the following structure?

Chlorocyclopentane

2-Chloro-1-methylcyclopentane

1-Methyl-2-chlorocyclopentane

1-Chloro-2-methylcyclopentane

Ans: D


Section 2



3-Fluorobutane

2-Fluorobutane

(S)-2-Fluorobutane

(R)-2-Fluorobutane

Ans: C


Section 2



2-Bromo-3-butylpentane

(2S)-Bromo-4,5-dimethylheptane

3,4-Dimethyl-6-bromoheptane

2-Bromo-4-methylhexane

Ans: B


Section 2


17. Which of the following is the correct structure for a compound with the IUPAC name of 2-bromo-3-methylbutane?

Ans: A


Section 2


18. Which of the following is the correct structure for a compound with the IUPAC name of 1-iodo-3-ethylcyclohexane?

Ans: B


Section 2


19. Which of the following is the correct structure for a compound with the IUPAC name of (2R)-2-fluorobutane?

Ans: D


Section 2


20. Which of the following compounds has a tertiary carbon?

Ans: B


Section 2


21. Provide an IUPAC name for the following compound.

Ans: 1,1-Dibromocyclopropane


Section 2


22. Provide an IUPAC name for the following compound.

Ans: 2-Chloro-5-fluorohexane


Section 2


23. On the following compound, label all of the primary, secondary, and tertiary carbons.

Ans:


Section 2


24. Identify the labeled carbon as primary, secondary, or tertiary.

Ans: tertiary


Section 2



Ans: primary


Section 2



Ans: secondary

Topic: Possible Mechanisms

Section 3


27. Provide a definition of a concerted reaction.

Ans: All bond breaking and making occurs at the same time.


Section 3


28. Which of the following is a reasonable definition of a concerted reaction?

It is a reaction which takes place in a series of steps.

It is a reaction which produces a loud noise.

It is a reaction in which all bond-breaking and bond-forming occurs at the same time.

It is a substitution reaction.

Ans: C


Section 3


29. Provide examples of the 4 patterns for steps in the mechanisms of substitution reactions.

Ans: 1. Nucleophilic attack, 2. Loss of a leaving group, 3. Proton transfer, and

4. Rearrangement


Section 3


30. Which of the following is not a possible step in a substitution reaction?

Ans: D


Section 3


31. Provide an arrow pushing mechanism for the following reaction.

Ans:


Section 3


32. Provide an arrow pushing mechanism and product for the following reaction.

Ans:


Section 3


33. When drawing an arrow-pushing mechanism, the tail of the arrow starts where?

At the bond that is being formed.

At the bond that is being broken.

At the source of electrons that is being moved.

At the location to which the electrons are being moved.

Ans: C or B


Section 3


34. When drawing an arrow-pushing mechanism, the head of the arrow goes where?

At the bond that is being formed.

At the bond that is being broken.

At the source of electrons that is being moved.

At the location to which the electrons are being moved.

Ans: D


Section 3


35. Which of the following shows the correct arrow for loss of a bromide leaving group?

Ans: A


Section 3


36. Provide an arrow-pushing mechanism for the following (intramolecular) reaction.

Ans:

Topic: SN2 Mechanism

Section 4


37. Which of the following is the rate law for the following SN2 reaction?

Rate = k[1-bromopropane]

Rate = k[NaCN]

Rate = k[NaCN][1-bromopropane]

Rate = k[NaCN]2

Ans: C


Section 4


38. Write the rate law for the following SN2 reaction.

Ans:


Section 4


39. Which of the following is the product of the following SN2 reaction?

Ans: C


Section 4


40. Which of the following is the product of the following SN2 reaction?

Ans: C


Section 4


41. Provide the SN2 product of the following reaction.

Ans:


Section 4


42. Provide a mechanism for this reaction.

Ans:


Section 4


43. Which of the following is a mechanism for an SN2 reaction?

Ans: C

Show arrows more carefully in B, C, D


Section 4


44. Which of the following is the product of the following reaction?

Ans: A


Section 4



Ans: D


Section 4



Ans: A


Section 4


47. What is the product of the following reaction?

Ans:


Section 4


48. What is the product of the following reaction?

Ans:


Section 4


49. From the given starting material, how could you stereospecifically form the given product?

Ans:


Section 4


50. Rank the following substrates from most to least reactive in an SN2 reaction.

A>B>C>D

D>C>B>A

A>C>B>D

D>C>B>A

Ans: C


Section 4



A. A>B>C>D

B. D>C>B>A

C. C>B>A>D

D. D>C>B>A

Ans: C


Section 4



A. A>B>C>D

B. D>C>B>A

C. C>B>A>D

D. D>C>A>B

Ans: B


Section 4



A. A>B>C>D

B. C>D>B>A

C. C>B>A>D

D. D>C>B>A

Ans: B


Section 4


54. Draw a reaction diagram for the following reaction.

Ans:


Section 4


55. Which of the following is the reaction diagram for an exothermic, concerted reaction?

Ans: C


Section 4


56. Given the following rate law, what will happen to the rate if the concentration of

MeI is doubled? Rate = k[Me3N][MeI] It will be doubled.

It will not change.

It will decrease in half.

It will increase very slightly.

Ans: A


Section 4


57. Given the following rate law, what will happen to the rate if the concentration of both reactants is doubled?

Rate = k[Me3N][MeI]

A. It will be doubled.

B. It will not change.

C. It will decrease in half.

D. It will increase 4-fold.

Ans: D


Section 4


58. Given the following rate law, what will happen to the rate if the concentration of MeI is doubled and the concentration of Me3N is halved?

Rate = k[Me3N][MeI]

A. It will be doubled.

B. It will not change.

C. It will decrease in half.

D. It will increase very slightly.

Ans: B


Section 5


59. Which of the following is the rate law for the following reaction?

Rate = k[H2O]

Rate = k[H2O][1-chloro-1-methylcyclohexane]

Rate = k[1-chloro-1-methylcyclohexane]

Rate = k[chloride ion]

Ans: C


Section 5


60. Provide the rate law for the following reaction.

Ans:


Section 5


61. Draw a reaction diagram for the following SN1 reaction.

Ans:


Section 5


62. Which of the following is a reaction diagram for an SN1 reaction that is endothermic?

Ans: B


Section 5



A>B>C>D

A>B>D>C

D>A>B>C

D>C>B>A

Ans: A


Section 5



A. A>B>C>D

B. A>B>D>C

C. C>A>B>D

D. C>D>B>A

Ans: D


Section 5



A. A>B>C>D

B. A>B>D>C

C. D>A>B>C

D. D>C>B>A

Ans: A


Section 5



A. A>B>C>D

B. A>B>D>C

C. C>B>A>D

D. D>A>B>C

Ans: C


Section 5


67. Why is a tertiary alkyl halide more reactive in an SN1 reaction than a secondary alkyl halide?

Ans: The tertiary cation is more stable.


Section 5


68. Provide a mechanism for the following SN1 reaction.

Ans:


Section 5



Ans: D


Section 5



Ans: B


Section 5



Ans: C


Section 5



Ans: A


Section 5


73. Provide the product of the following reaction.

Ans:


Section 5


74. What is the product of the following reaction. Include stereochemistry.

Ans:


Section 5


75. What is the product of the following reaction. Include stereochemistry.

Ans: A


Section 5


76. Why does a racemate form at the leaving group carbon in an SN1 reaction?

Ans: Because the cationic intermediate is planar and there is equal likelihood of attack of the nucleophile from either face, leading to equal formation of both enantiomers.

Topic: Drawing the Complete SN1 Mechanism

Section 6


77. Which of the following is a good leaving group?

-OH

-CH3

-Br

-NH2

Ans: C


Section 6


78. What is the best leaving group in the following compound?

Ans:


Section 6


79. Circle the best leaving group in the following compound.

Ans:


Section 6


80. Which of the following must be protonated in order to be a good leaving group?

Cl

Br

NMe2

OH2

Ans: C


Section 6


81. Which of the following nucleophiles will require a proton transfer step at the end of the reaction?

NMe3

I–

OH–

H2S

Ans: D


Section 6


82. Provide an example of a nucleophile that will require a proton transfer step at the end of the reaction.

Ans: Any protic nucleophile (so there are many answers).


Section 6


83. Which of the following alkyl halides would likely undergo rearrangement during an SN1 reaction?

Ans: B


Section 6


84. Which of the following is the major product for the following SN1 reaction?

Ans: B


Section 6


85. Draw the anticipated major product for the following reaction.

Ans:


Section 6


86. Draw an energy diagram for the following reaction.

Ans:

Drawing the Complete SN1 Mechanism

Section 6


87. Draw a mechanism for the following reaction.

Ans:


Section 6


88. What is the anticipated major product for the following reaction?

Ans:


Section 6


89. What is the mechanism for the following reaction?

Ans:


Section 6


90. What is the rate law for the following SN1 reaction?

Ans:


Section 7


91. For the following reaction, which of the following is the mechanism?

SN1

SN2

Protonation

Elimination

Ans: B


Section 7


92. For the following reaction, which of the following is the product?

Ans: D


Section 7


93. For the following reaction, which of the following is the rate law?

k[HBr] k[1-pentanol]

k[HBr][1-pentanol]

k[HBr]2

Ans: C


Section 7



Ans:

Drawing the Complete SN2 Mechanism

Section 7


95. For the following reaction, which of the following is the mechanism?

A. SN1

B. SN2

C. Protonation

D. Elimination

Ans: B


Section 7


96. For the following reaction, which of the following is the product?

Ans: B


Section 7


97. For the following reaction, which of the following is the rate law?

Rate = k[MeI]

Rate = k[t-butanol]

Rate = k[MeI][t-butanol]

Rate = k[OH]

Ans: C


Section 7



Ans:


Section 7


99. For the following reaction, provide the mechanism.

Ans:


Section 7


100. For the following reaction, draw the product.

Ans:


Section 7


101. For the following reaction, provide the rate law.

Ans:


Section 7


102. For the following reaction, provide an energy diagram.

Ans:

Determining Which Mechanism

Section 8


103. What set of reaction conditions should favor an SN2 reaction on 2-bromo-3methylbutane?

weak nucleophile in a protic solvent weak

nucleophile in an aprotic solvent strong

nucleophile in a protic solvent strong

nucleophile in an aprotic solvent

Ans: D

Topic: Determining Which Mechanism

Section 8


104. What set of reaction conditions should favor an SN1 reaction on 2-bromo-3methylbutane?

A. weak nucleophile in a protic solvent

B. weak nucleophile in an aprotic solvent

C. strong nucleophile in a protic solvent

D. strong nucleophile in an aprotic solvent

Ans: A


Section 8


105. What reaction mechanism is most likely for substitution on the following compound?

SN1

SN2

Either

Neither

Ans: C


Section 8



A. SN1

B. SN2

C. Either

D. Neither

Ans: B


Section 8



A. SN1

B. SN2

C. Either

D. Neither

Ans: C


Section 8



A. SN1

B. SN2

C. Either

D. Neither

Ans: A


Section 8



A. SN1

B. SN2

C. Either

D. Neither

Ans: C


Section 8



A. SN1

B. SN2

C. Either

D. Neither

Ans: D


Section 8


111. Is the following nucleophile strong or weak?

I–

Strong

Weak

Not a nucleophile

Ans: A


Section 8



H2O

A. Strong

B. Weak

C. Not a nucleophile

Ans: B


Section 8



Li+

A. Strong

B. Weak


Ans: C


Section 8



HO–

A. Strong

B. Weak


Ans: A


Section 8



H2S

A. Strong

B. Weak


Ans: A


Section 8


116. Provide an example of a strong nucleophile.

Ans: There are many possible answers.


Section 8



CN–

A. Strong

B. Weak


Ans: A


Section 8



Na+

A. Strong

B. Weak


Ans: C


Section 8


119. Why do polar aprotic solvents favor SN2 reactions?

Ans: They raise the energy of the nucleophile, giving a smaller energy of activation for the SN2 pathway. OR They can solvate cations, making the anion more “naked” and thus more nucleophilic.


Section 8


120. What type of solvent would be best for obtaining an optically active product in the following reaction?

polar protic polar

aprotic apolar

aprotic water

Ans: A


Section 8


121. Which of the following leaving groups would you expect to be the best?

Ans: D


Section 8


122. Which of the following solvents is not protic?

EtOH

H2O NH3

hexane

Ans: D


Section 8


123. What type of solvent is ethanol (EtOH)?

polar aprotic apolar

aprotic polar protic

Ans: C

Topic: Selecting Reagents

Section 9


124. Which reagents would you use for the following reaction?

H2S in water

H2S in DMSO

NaSH in water

NaSH in DMSO

Ans: D


Section 9



HN3 in water

HN3 in acetonitrile

NaN3 in water

NaN3 in acetonitrile

Ans: D


Section 9



HCl in water

HCl in ether

NaCl in water

NaCl in DMF

Ans: A or B


Section 9



HBr in water

NaBr in water

Ethyl bromide

Ethyl iodide

Ans: C


Section 9



NaOH in water

NaOH in acetonitrile

Water

HCl in water

Ans: C


Section 9



methanol methanol in

acetonitrile NaOMe in

water

NaOMe in acetonitrile

Ans: D


Section 9


130. How would you accomplish the following transformation?

Ans: MeOH (SN1 mechanism)


Section 9



Ans: NaSH in a polar aprotic solvent


Section 9



Ans: H3CCH2Br


Section 9



Ans:


Section 9



Ans: HBr


Section 9



Ans:


Section 9


136. Which of the following sets of reagents would best accomplish the following transformation?

Ans: C


Section 9



Ans: A


Section 9



Ans: D

Test Bank for Organic Chemistry 1st Edition by Klein · PDF fileTest Bank for Organic...

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