Question 1

The conjugated portion of the following molecule is circled.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following electronic transitions is apparent in the ultraviolet-visible spectrum of 1,3-butadiene?

Accepted Answer

A)  "n  →\rarr→   π\piπ *"
B)  " π\piπ   →\rarr→   π\piπ  *"
C)  "  σ\sigmaσ→\rarr→   π\piπ  *"
D)  "  σ\sigmaσ   →\rarr→   π\piπ " E) A) and D)
F) B) and C)

Question 3

What is the thermodynamic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Accepted Answer

A)  3,4-dibromo-1-butene
B)  (
E)  -1,4-dibromo-2-butene
C)  (Z) -1,4-dibromo-2-butene
D)  (Z) -2,3-dibromo-2-buteneE) A) and B)
F) B) and C)

Question 4

What is the IUPAC name of the following compound?

Accepted Answer

A)  (R) -3-vinyl-1-butene
B)  3-methyl-1,5-pentadiene
C)  3-methyl-1,4-pentadiene
D)  (R) -3-methyl-1,4-pentadieneE) B) and D)
F) B) and C)

Question 5

What is (are)  the major organic product(s)  formed in the following reaction?

Accepted Answer

A)  only 1
B)  only 2
C)  only 3
D)  1, 2 and 3E) B) and C)
F) A) and B)

Question 6

Consider the reaction below to answer the following question(s):  Enter the appropriate letter in the blank for each the following statements.
-Based on the following table.
Compound
$\lambda$max (nm)
W
190
X
340
Y
560
Z
250
Compound ______ has the largest energy difference between the HOMO and LUMO.

Accepted Answer

Question 7

What is (are)  the major organic product(s)  formed in the following reaction?

Accepted Answer

A)  only 1
B)  only 1 and 3
C)  only 2 and 4
D)  only 1 and 4E) All of the above
F) B) and C)

Question 8

The conjugated portion of the following molecule is circled.

Accepted Answer

A) True 
 B)False

Question 9

Electrophilic addition reaction of conjugated dienes that occur at high temperature and/or long reaction times (reversible conditions) are said to be under kinetic control.

Accepted Answer

A) True 
 B)False

Question 10

For a diene to undergo a Diels-Alder reaction it must be able to adopt an s-trans conformation.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following is not a major organic product obtained from the addition of 1 mole of bromine to (E) -1,3-pentadiene?

Accepted Answer

A)  (
E)  -4,5-dibromo-2-pentene
B)  3,4-dibromo-1-pentene
C)  (
E)  -1,4-dibromo-2-pentene
D)  (
E)  -1,2-dibromo-2-penteneE) A) and B)
F) None of the above

Question 12

For Diels-Alder cycloaddition reactions to take place most rapidly and in highest yield a dienophile must be substituted with electron-donating groups.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) A) and B)
F) None of the above

Question 14

Consider the reaction below to answer the following question(s) .  Fill in the blank in the question with the appropriate letter.
-The dienophile in the reaction is ____.

Accepted Answer

A)  A
B)  B
C)  CD) All of the above
E) A) and B)

Question 15

The following spectrum could arise from $\pi$ to $\pi$* transitions.

Accepted Answer

A) True 
 B)False

Question 16

Sigmatropic shifts, cycloaddition reactions and anuulation reactions are all examples of pericyclic reactions.

Accepted Answer

A) True 
 B)False

Question 17

What are the units of  λ\lambdaλ max in ultraviolet-visible spectroscopy?

Accepted Answer

A)  J.mol-1
B)  M-1
C)  nm
D)  none,  λ\lambdaλ max is a dimensionless quantity E) B) and D)
F) A) and B)

Question 18

Consider the reaction below to answer the following question(s) :  Enter the appropriate letter in the blank for each the following statements.
-The product that results from 1,4-addition is _____.

Accepted Answer

A)  A
B)  B
C)  C
D)  DE) B) and C)
F) A) and C)

Question 19

What is the major organic product obtained from the following reaction?

Accepted Answer

The answer of What is the major organic product obtained...

Question 20

What is (are)  the major organic product(s)  formed in the following reaction?

Accepted Answer

A)  only 1
B)  only 3
C)  only 1 and 3
D)  only 2 and 4E) All of the above
F) None of the above

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Correct Answer
verified

For Diels-Alder cycloaddition reactions to take place most rapidly and in highest yield a dienophile must be substituted with electron-donating groups.

Correct Answer
verified

The conjugated portion of the following molecule is circled.

Correct Answer
verified

What is (are) the major organic product(s) formed in the following reaction?

Correct Answer
verified

For a diene to undergo a Diels-Alder reaction it must be able to adopt an s-trans conformation.

Correct Answer
verified

What is (are) the major organic product(s) formed in the following reaction?

Correct Answer
verified

Which of the following electronic transitions is apparent in the ultraviolet-visible spectrum of 1,3-butadiene?

Correct Answer
verified

What is (are) the major organic product(s) formed in the following reaction?

Correct Answer
verified

Which of the following is not a major organic product obtained from the addition of 1 mole of bromine to (E) -1,3-pentadiene?

Correct Answer
verified

What are the units of $\lambda$ _max in ultraviolet-visible spectroscopy?

Correct Answer
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The conjugated portion of the following molecule is circled.

Correct Answer
verified

What is the IUPAC name of the following compound?

Correct Answer
verified

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Correct Answer
verified

Electrophilic addition reaction of conjugated dienes that occur at high temperature and/or long reaction times (reversible conditions) are said to be under kinetic control.

Correct Answer
verified

What is the thermodynamic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Correct Answer
verified

What is the major organic product obtained from the following reaction?

Correct Answer
verified

Consider the reaction below to answer the following question(s) : Enter the appropriate letter in the blank for each the following statements. -The product that results from 1,4-addition is _____.

Correct Answer
verified

Consider the reaction below to answer the following question(s) . Fill in the blank in the question with the appropriate letter. -The dienophile in the reaction is ____.

Correct Answer
verified

Sigmatropic shifts, cycloaddition reactions and anuulation reactions are all examples of pericyclic reactions.

Correct Answer
verified

The following spectrum could arise from $\pi$ to $\pi$ * transitions. $The following spectrum could arise from \pi to \pi * transitions.$

Correct Answer
verified

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Correct AnswerverifiedShow Answer

For Diels-Alder cycloaddition reactions to take place most rapidly and in highest yield a dienophile must be substituted with electron-donating groups.

Correct AnswerverifiedShow Answer

The conjugated portion of the following molecule is circled.

Correct AnswerverifiedShow Answer

What is (are) the major organic product(s) formed in the following reaction?

Correct AnswerverifiedShow Answer

For a diene to undergo a Diels-Alder reaction it must be able to adopt an s-trans conformation.

Correct AnswerverifiedShow Answer

What is (are) the major organic product(s) formed in the following reaction?

Correct AnswerverifiedShow Answer

Which of the following electronic transitions is apparent in the ultraviolet-visible spectrum of 1,3-butadiene?

Correct AnswerverifiedShow Answer

What is (are) the major organic product(s) formed in the following reaction?

Correct AnswerverifiedShow Answer

Which of the following is not a major organic product obtained from the addition of 1 mole of bromine to (E) -1,3-pentadiene?

Correct AnswerverifiedShow Answer

What are the units of λ\lambdaλ max in ultraviolet-visible spectroscopy?

Correct AnswerverifiedShow Answer

The conjugated portion of the following molecule is circled.

Correct AnswerverifiedShow Answer

What is the IUPAC name of the following compound?

Correct AnswerverifiedShow Answer

Which of the following energy diagrams represents the electronic state of butadiene after absorption of radiation?

Correct AnswerverifiedShow Answer

Electrophilic addition reaction of conjugated dienes that occur at high temperature and/or long reaction times (reversible conditions) are said to be under kinetic control.

Correct AnswerverifiedShow Answer

What is the thermodynamic product obtained from the addition of 1 mole of bromine to 1,3-butadiene?

Correct AnswerverifiedShow Answer

What is the major organic product obtained from the following reaction?

Correct AnswerverifiedShow Answer

Consider the reaction below to answer the following question(s) : Enter the appropriate letter in the blank for each the following statements. -The product that results from 1,4-addition is _____.

Correct AnswerverifiedShow Answer

Consider the reaction below to answer the following question(s) . Fill in the blank in the question with the appropriate letter. -The dienophile in the reaction is ____.

Correct AnswerverifiedShow Answer

Sigmatropic shifts, cycloaddition reactions and anuulation reactions are all examples of pericyclic reactions.

Correct AnswerverifiedShow Answer

The following spectrum could arise from π\piπ to π\piπ * transitions.

Correct AnswerverifiedShow Answer

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What are the units of $\lambda$ _max in ultraviolet-visible spectroscopy?

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The following spectrum could arise from $\pi$ to $\pi$ * transitions. $The following spectrum could arise from \pi to \pi * transitions.$

Correct Answer
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