Question 1

Which of the following electronic transitions is common in the UV spectrum of 1,3-butadiene?

Accepted Answer

A)  s®p
B)  s®p*
C)  n ®p*
D)  p®p*E) B) and C)
F) C) and D)

Question 2

Which of the following is the appropriate term for the mechanism of the addition of HBr to 1,3-dienes?

Accepted Answer

A)  Nucleophilic addition
B)  Electrophilic addition
C)  Free radical addition
D)  Conjugate additionE) B) and D)
F) B) and C)

Question 3

Which of the following is an example of a bridged bicyclic system?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and C)
F) C) and D)

Question 4

Rank the following dienophile in order of increasing reactivity in a Diels-Alder reaction,listing the least reactive first.

Accepted Answer

A)  I 
B)  III 
C)  II 
D)  III < II < IE) All of the above
F) A) and B)

Question 5

Which of the following is the most reactive diene in a Diels-Alder reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and C)
F) B) and D)

Question 6

Which of the following is a major resonance contributor to the first structure?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and D)

Question 7

Rank the following compounds in order of increasing stability,putting the least stable first.

Accepted Answer

A)  I 
B)  III 
C)  II 
D)  III < I < IIE) A) and B)
F) A) and C)

Question 8

What is the major product of the following reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and D)
F) None of the above

Question 9

What is the major organic product of the following reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and C)

Question 10

Which of the following is the least reactive diene in a Diels-Alder reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) All of the above D

Question 11

What is the major product of the following reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and C)

Question 12

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

Accepted Answer

A)  Only I
B)  Only II
C)  Only I and II
D)  I,II,and IIIE) C) and D)
F) B) and C)

Question 13

What diene and dienophile are used in a Diels-Alder reaction to prepare the following compound?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) None of the above

Question 14

Which of the following is (are) conjugated dienes?

Accepted Answer

A)  Only I
B)  Only II
C)  Only I and II
D)  I,II,and IIIE) C) and D)
F) B) and C)

Question 15

Which triene has the largest heat of hydrogenation?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and C)
F) All of the above D

Question 16

Which of the following statements about the Diels-Alder reaction is true?

Accepted Answer

A)  The diene can react only when it adopts the s-trans conformation.
B)  Electron-withdrawing substituents in the diene increase reaction rate.
C)  Electron-donating substituents in the dienophile increase the reaction rate.
D)  The stereochemistry of the dienophile is retained in the product.E) All of the above
F) B) and C)

Question 17

Which of the following is not a feature of the Diels-Alder reaction?

Accepted Answer

A)  They are initiated by peroxides.
B)  They form new six-membered rings.
C)  Three π bonds break.
D)  They are concerted.E) A) and C)
F) A) and B)

Question 18

What is the kinetic product obtained from the addition of 1 equivalent of HBr to 1,3-butadiene?

Accepted Answer

A)  3-Bromo-1-butene
B)  1-Bromo-2-butene
C)  2-Bromo-2-butene
D)  2-Bromo-1-buteneE) A) and B)
F) A) and C)

Question 19

Which triene absorbs the longest wavelength of UV light?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and B)
F) A) and C) A

Question 20

Which of the following is not a product obtained from the addition of 1 equivalent of HBr to (E) -1,3-pentadiene?

Accepted Answer

A)  (
E)  -4-Bromo-2-pentene
B)  (
E)  -1-Bromo-2-pentene
C)  3-Bromo-1-pentene
D)  (
E)  -3-Bromo-2-penteneE) A) and B)
F) B) and C)

Exam 14: Conjugation, resonance, and Dienes

Which of the following electronic transitions is common in the UV spectrum of 1,3-butadiene?

Correct AnswerverifiedShow Answer

Which of the following is the appropriate term for the mechanism of the addition of HBr to 1,3-dienes?

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Which of the following is an example of a bridged bicyclic system?

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Rank the following dienophile in order of increasing reactivity in a Diels-Alder reaction,listing the least reactive first.

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Which of the following is the most reactive diene in a Diels-Alder reaction?

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Which of the following is a major resonance contributor to the first structure?

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Rank the following compounds in order of increasing stability,putting the least stable first.

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What is the major product of the following reaction?

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What is the major organic product of the following reaction?

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Which of the following is the least reactive diene in a Diels-Alder reaction?

Correct AnswerverifiedD

What is the major product of the following reaction?

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

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What diene and dienophile are used in a Diels-Alder reaction to prepare the following compound?

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Which of the following is (are) conjugated dienes?

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Which triene has the largest heat of hydrogenation?

Correct AnswerverifiedD

Which of the following statements about the Diels-Alder reaction is true?

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Which of the following is not a feature of the Diels-Alder reaction?

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What is the kinetic product obtained from the addition of 1 equivalent of HBr to 1,3-butadiene?

Correct AnswerverifiedShow Answer

Which triene absorbs the longest wavelength of UV light?

Correct AnswerverifiedA

Which of the following is not a product obtained from the addition of 1 equivalent of HBr to (E) -1,3-pentadiene?

Correct AnswerverifiedShow Answer

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D

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D

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A

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