Question 1

Why carbonyl groups of aldehydes and ketones on conjugation with carbon-carbon double bonds show strong absorption in the ultraviolet spectrum?

Accepted Answer

The presence of conjugation in aldehydes...

Question 2

Which of the following processes takes place upon absorption of ultraviolet-visible radiation?

Accepted Answer

A)   bond vibration
B)   electron excitation
C)   nuclear spin flip
D)   electron spin flipE) A) and C)
F) None of the above

Question 3

What are the units of ε in ultraviolet-visible spectroscopy?

Accepted Answer

A)   M−1⋅cm−1
B)   M⋅cm
C)   J⋅mol−1⋅M−1
D)   none, ε is a dimensionless quantityE) A) and D)
F) A) and B)

Question 4

Identify the product of the given reaction. ​

Accepted Answer

A)   I
B)   II
C)   IV
D)   IIIE) A) and D)
F) A) and C)

Question 5

Which of the following terms describes the mechanism for the addition of Br2 to butadiene?

Accepted Answer

A)   electrophilic addition
B)   nucleophilic addition
C)   pericyclic addition
D)   conjugate additionE) B) and D)
F) A) and D)

Question 6

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

Accepted Answer

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

Question 7

What is the systematic IUPAC name of the following compound?

Accepted Answer

A)   (3S,4
E)  -3-ethyl-3,4-dimethyl-1,4-hexadiene
B)   (3R,4
E)  -3-ethyl-3,4-dimethyl-1,4-hexadiene
C)   (3S,4Z) -3-ethyl-3,4-dimethyl-1,4-hexadiene
D)   (3R,4Z) -3-ethyl-3,4-dimethyl-1,4-hexadieneE) A) and C)
F) A) and D)

Question 8

Which of the following alkenes undergoes the least exothermic hydrogenation upon treatment with H2/Pd 2/Pd   A)  1 B)  2 C)  3 D)  4" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 9

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 10

Consider the reaction below to answer the following question(s):  Enter the appropriate letter in the blank for each the following statements.
-The electrophile in this reaction is ____.

Accepted Answer

The answer of Consider the reaction below to answer the...

Question 11

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

Accepted Answer

The answer of Consider the reaction below to answer the...

Question 12

Which of the following reaction coordinate diagrams explains the formation of different thermodynamic (T)  and kinetic products from the same reactants (R) ?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) A) and B)
F) A) and C)

Question 13

What are the two major organic products obtained from the following reaction?

Accepted Answer

The answer of What are the two major organic products...

Question 14

Draw two resonance structures of the reactive intermediate that accounts for the formation of 1,2- and 1,4-addition products upon reaction of 1,3-butadiene with one equivalent of HBr.

Accepted Answer

The answer of Draw two resonance structures of the reactive...

Question 15

Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H2 in the presence of a catalyst). Provide a brief explanation for your choice ?

Accepted Answer

1,4-Cyclohexadiene has a great...

Question 16

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

Accepted Answer

A) True 
 B)False

Question 17

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) None of the above
F) B) and C)

Question 18

Which of the following energy diagrams represents the electronic state of the ground state of 1,3-butadiene?

Accepted Answer

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

Question 19

Provide the structures of the constitutional isomers of the two major organic products obtained from the following reaction?

Accepted Answer

The answer of Provide the structures of the constitutional isomers...

Question 20

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) C) and D)
F) B) and C)

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

Which of the following processes takes place upon absorption of ultraviolet-visible radiation?

Correct AnswerverifiedShow Answer

Why carbonyl groups of aldehydes and ketones on conjugation with carbon-carbon double bonds show strong absorption in the ultraviolet spectrum?

Correct AnswerverifiedThe presence of conjugation in aldehydes...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

What are the two major organic products obtained from the following reaction?

Correct AnswerverifiedShow Answer

What is the systematic IUPAC name of the following compound?

Correct AnswerverifiedShow Answer

Which of the following reaction coordinate diagrams explains the formation of different thermodynamic (T) and kinetic products from the same reactants (R) ?

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

Which of the following terms describes the mechanism for the addition of Br2 to butadiene?

Correct AnswerverifiedShow Answer

Draw two resonance structures of the reactive intermediate that accounts for the formation of 1,2- and 1,4-addition products upon reaction of 1,3-butadiene with one equivalent of HBr.

Correct AnswerverifiedShow Answer

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

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

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Consider the reaction below to answer the following question(s): Enter the appropriate letter in the blank for each the following statements. -The electrophile in this reaction is ____.

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Identify the product of the given reaction. ​

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

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Provide the structures of the constitutional isomers of the two major organic products obtained from the following reaction?

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

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Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H2 in the presence of a catalyst). Provide a brief explanation for your choice ?

Correct Answerverified1,4-Cyclohexadiene has a great...View AnswerShow Answer

Which of the following alkenes undergoes the least exothermic hydrogenation upon treatment with H2/Pd

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What are the units of ε in ultraviolet-visible spectroscopy?

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Which of the following energy diagrams represents the electronic state of the ground state of 1,3-butadiene?

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The presence of conjugation in aldehydes...
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Which of the following terms describes the mechanism for the addition of Br₂ to butadiene?

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Identify the product of the given reaction.

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Which of 1,3-cyclohexadiene and 1,4-cyclohexadiene has the greatest heat of hydrogenation (i.e., the most exothermic reaction with H₂ in the presence of a catalyst). Provide a brief explanation for your choice ?

Correct Answer
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1,4-Cyclohexadiene has a great...
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Which of the following alkenes undergoes the least exothermic hydrogenation upon treatment with H₂/Pd

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