Question 1

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 bromine.

Accepted Answer

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

Question 2

Which of the following arrangements of p atomic orbitals gives the lowest energy p-bonding molecular orbital of 1,3-butadiene?

Accepted Answer

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

Question 3

What is the IUPAC name of the following compound?

Accepted Answer

A)   2,3-dimethyl-2,4-pentadiene
B)   (Z) -2,3-dimethyl-2,4-pentadiene
C)   3,4-dimethyl-1,3-pentadiene
D)   (Z) -3,4-dimethyl-1,3-pentadieneE) None of the above
F) All of the above

Question 4

Which of the following arrangements of p atomic orbitals of 1,3-butadiene has the greatest number of nodes?

Accepted Answer

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

Question 5

Which of the following are conjugated dienes?

Accepted Answer

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

Question 6

Which of the following has the highest value of lmax in the ultraviolet-visible spectrum? max in the ultraviolet-visible spectrum?   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) B) and C)
F) All of the above

Question 7

What is the kinetic 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) C) and D)
F) B) and C)

Question 8

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) A) and C)

Question 9

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

Accepted Answer

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

Question 10

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 11

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 12

Which of the following is(are)  formed upon addition of 1 mol of Br2 to 1,3-cyclohexane? 2 to 1,3-cyclohexane?   A)  only 2 B)  only 1 and 3 C)  only 2 and 4 D)  1, 2 and 3" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 13

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

Accepted Answer

A)   J*mol-1
B)   M-1
C)   nm
D)   none, lmax is a dimensionless quantityE) C) and D)
F) B) and D)

Question 14

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

Question 15

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) A) and D)
F) A) and C) A

Question 16

What are the units of absorbance, A, in ultraviolet-visible spectroscopy?

Accepted Answer

A)   J*mol-1
B)   nm*mol-1
C)   J*mol-1*M-1
D)   none, A is a dimensionless quantityE) C) and D)
F) A) and C)

Question 17

What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition?

Accepted Answer

A)   cyclic bromonium cation
B)   allylic cation
C)   allylic radical
D)   dienophileE) A) and B)
F) A) and C)

Question 18

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

Question 19

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) C) and D)
F) All of the above

Question 20

Which of the following arrangements of p atomic orbitals gives the highest energy p-antibonding molecular orbital of 1,3-butadiene?

Accepted Answer

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

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

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 bromine.

Correct AnswerverifiedShow Answer

Which of the following arrangements of p atomic orbitals gives the lowest energy p-bonding molecular orbital of 1,3-butadiene?

Correct AnswerverifiedShow Answer

What is the IUPAC name of the following compound?

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Which of the following arrangements of p atomic orbitals of 1,3-butadiene has the greatest number of nodes?

Correct AnswerverifiedShow Answer

Which of the following are conjugated dienes?

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Which of the following has the highest value of lmax in the ultraviolet-visible spectrum?

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

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

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

Correct AnswerverifiedB

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

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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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Which of the following is(are) formed upon addition of 1 mol of Br2 to 1,3-cyclohexane?

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

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

Correct AnswerverifiedC

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

Correct AnswerverifiedA

What are the units of absorbance, A, in ultraviolet-visible spectroscopy?

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What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition?

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

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What is the systematic IUPAC name of the following compound?

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Which of the following arrangements of p atomic orbitals gives the highest energy p-antibonding molecular orbital of 1,3-butadiene?

Correct AnswerverifiedShow Answer

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Which of the following has the highest value of l_max in the ultraviolet-visible spectrum?

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B

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Which of the following is(are) formed upon addition of 1 mol of Br₂ to 1,3-cyclohexane?

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

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C

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

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A

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