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 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 3

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

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

Question 4

What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H2/Pd (more exothermic > less exothermic) ? 2/Pd (more exothermic > less exothermic) ?   A) 1 > 2 > 3 B) 3 > 1 > 2 C) 2 > 1 > 3 D) 3 > 2 > 1" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

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

Question 5

The following compound could act as a diene in a Diels-Alder reaction.

Accepted Answer

A) True 
 B)False

Question 6

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 7

Consider the following structure.  This substance could be produced by the reaction of the following diene and dienophile.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following electronic transitions is (are)  apparent in the ultraviolet-visible spectrum of acrolein, H2C=CHCHO?
1) n   →\rarr→   π\piπ *
2)  π\piπ    →\rarr→   π\piπ *
3)   σ\sigmaσ→\rarr→   π\piπ *

Accepted Answer

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

Question 9

What is the IUPAC name of the following compound?

Accepted Answer

(E)-2,3-di...

Question 10

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

Question 11

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 12

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

Question 13

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) A) and B)
F) A) and C)

Question 14

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

Question 15

When an organic molecule is irradiated with ultraviolet radiation, the energy absorbed by the molecule corresponds to the amount necessary to excite electrons from one molecular orbital to another.

Accepted Answer

A) True 
 B)False

Question 16

What quantity is abbreviated as  ε\varepsilonε  in ultraviolet-visible spectroscopy?

Accepted Answer

A)  absorbance
B)  molecular absorptivity
C)  intensity of transmitted light
D)  wavelength of maximum absorbance E) B) and C)
F) All of the above

Question 17

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

Question 18

The following two compounds could be easily distinguished by NMR, IR, UV or MS spectra.

Accepted Answer

A) True 
 B)False

Question 19

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 20

Which of the following laws relates absorbance to the concentration of a sample and the pathlength in ultraviolet-visible spectroscopy?

Accepted Answer

A)  Buzz-Beer law
B)  Beer-Lambert law
C)  Duff-Beer law
D)  Christopher-Lambert lawE) A) and C)
F) A) and B)

Exam 20: Dienes, Conjugated Systems, and Pericyclic Reactions

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

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

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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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Consider the following structure. This substance could be produced by the reaction of the following diene and dienophile.

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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.

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What quantity is abbreviated as ε\varepsilonε in ultraviolet-visible spectroscopy?

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What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H2/Pd (more exothermic > less exothermic) ?

Correct AnswerverifiedShow Answer

Which of the following laws relates absorbance to the concentration of a sample and the pathlength in ultraviolet-visible spectroscopy?

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The following compound could act as a diene in a Diels-Alder reaction.

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What is the IUPAC name of the following compound?

Correct Answerverified(E)-2,3-di...View AnswerShow Answer

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

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When an organic molecule is irradiated with ultraviolet radiation, the energy absorbed by the molecule corresponds to the amount necessary to excite electrons from one molecular orbital to another.

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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 electronic transitions is (are) apparent in the ultraviolet-visible spectrum of acrolein, H2C=CHCHO? 1) n →\rarr→ π\piπ * 2) π\piπ →\rarr→ π\piπ * 3) σ\sigmaσ→\rarr→ π\piπ *

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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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The following two compounds could be easily distinguished by NMR, IR, UV or MS spectra.

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

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What is the systematic IUPAC name of the following compound?

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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.

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What quantity is abbreviated as $\varepsilon$ in ultraviolet-visible spectroscopy?

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What is the correct order of exothermicity for hydrogenation of the following hexadienes upon treatment with H₂/Pd (more exothermic > less exothermic) ?

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(E)-2,3-di...
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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 electronic transitions is (are) apparent in the ultraviolet-visible spectrum of acrolein, H₂C=CHCHO? 1) n $\rarr$ $\pi$ * 2) $\pi$ $\rarr$ $\pi$ * 3) $\sigma$ $\rarr$ $\pi$ *

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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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