Question 1

Rank the following dienes in increasing order of stability (least to most) .

Accepted Answer

A)  I<IV<III<II
B)  III<II<I<IV
C)  IV<II<III<I
D)  II<IV<III<I
E)  I<III<II<IV

Question 2

Which one of the following dienes will have the least heat of hydrogenation?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  V

Question 3

Which one of the following represents the LUMO of 1,3,5-hexatriene?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  V

Question 4

How many  π\piπ -bonding molecular orbitals does 1,3-pentadiene have?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  none

Question 5

Which of the following compound(s) have the longest  λ\lambdaλ max? max?   A) I B) II C) III D) IV E) V " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  V

Question 6

Which one of the following dienes is most stable?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV C

Question 7

Which major product(s) are formed for the following reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  V A

Question 8

Which one of the following dienophiles is least reactive in the Diels-Alder reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  V

Question 9

Which statement is NOT true about the Diels-Alder reaction?

Accepted Answer

A)  It is a [4+2] cycloaddition reaction.
B)  The diene must be in the s-cis conformation to react.
C)  Most Diels-Alder reactions are reversible.
D)  It is a sigmatropic rearrangement.
E)  Electron donating groups on the diene and electron withdrawing groups on the dieneophile favor product formation.

Question 10

Predict the major product for the following reaction.

Accepted Answer

The answer of Predict the major product for the following...

Question 11

What is the correct classification of the following pericyclic reaction?

Accepted Answer

A)  electrophilic addition
B)  sigmatropic rearrangement
C)  cycloaddition
D)  electrocyclic reaction
E)  C & D

Question 12

Which one of the following compounds is not a product of reaction between 1,3-butadiene and HBr?

Accepted Answer

A)  (S) -3-bromo-1-butene
B)  (R) -3-bromo-1-butene
C)  (
E)  -1-bromo-2-butene
D)  (Z) -1-bromo-2-butene
E)  (Z) -2-bromo-2-butene

Question 13

Provide the structure for 1,2 addition product for the following reaction and explain why it is a major product rather than 1,4 addition product.

Accepted Answer

<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> 1,2-product is the major one ...

Question 14

What is the correct classification of the following pericyclic reaction?

Accepted Answer

A)  electrophilic addition
B)  sigmatropic rearrangement
C)  cycloaddition
D)  electrocyclic reaction
E)  C & D

Question 15

How many electrons does the LUMO of 2,4-hexadiene have in its ground state?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  0

Question 16

The Diels Alder reaction is a concerted reaction,which means

Accepted Answer

A)  The product contains a cyclic ring
B)  The diene must be in the s-cis conformation to react.
C)  All changes in bonding (bond making and bond breaking) occur simultaneously.
D)  It is an endothermic reaction
E)  Both exo and endo products are formed

Question 17

Which of the following diene(s) can not undergo the Diels-Alder reaction?

Accepted Answer

A)  I
B)  II
C)  III
D)  IV
E)  I & IV

Question 18

Which one of the following dienes is most stable?

Accepted Answer

A)  CH3CH=CHCH=CHCH3
B)  CH3CH=CHCH2CH=CH2
C)  CH2=CHCH2CH2CH=CH2
D)  CH2=CHCH(CH3) CH=CH2
E)  CH3CH=C=CHCH2CH3 A

Question 19

Predict the product for the following reaction.

Accepted Answer

The answer of Predict the product for the following reaction....

Question 20

Predict the possible products for the following reaction and provide a curved arrow mechanism for the formation of these products.

Accepted Answer

The answer of Predict the possible products for the following...

Exam 17: Conjugated Pi Systems and Pericyclic Reactions

Rank the following dienes in increasing order of stability (least to most) .

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Which one of the following dienes will have the least heat of hydrogenation?

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Which one of the following represents the LUMO of 1,3,5-hexatriene?

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How many π\piπ -bonding molecular orbitals does 1,3-pentadiene have?

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Which of the following compound(s) have the longest λ\lambdaλ max?

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Which one of the following dienes is most stable?

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Which major product(s) are formed for the following reaction?

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Which one of the following dienophiles is least reactive in the Diels-Alder reaction?

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Which statement is NOT true about the Diels-Alder reaction?

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Predict the major product for the following reaction.

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What is the correct classification of the following pericyclic reaction?

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Which one of the following compounds is not a product of reaction between 1,3-butadiene and HBr?

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Provide the structure for 1,2 addition product for the following reaction and explain why it is a major product rather than 1,4 addition product.

Correct Answerverified 1,2-product is the major one ...View AnswerShow Answer

What is the correct classification of the following pericyclic reaction?

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How many electrons does the LUMO of 2,4-hexadiene have in its ground state?

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The Diels Alder reaction is a concerted reaction,which means

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Which of the following diene(s) can not undergo the Diels-Alder reaction?

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Which one of the following dienes is most stable?

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Predict the product for the following reaction.

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Predict the possible products for the following reaction and provide a curved arrow mechanism for the formation of these products.

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How many $\pi$ -bonding molecular orbitals does 1,3-pentadiene have?

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Which of the following compound(s) have the longest $\lambda$ _max? $Which of the following compound(s) have the longest \lambda <sub>max</sub>? A) I B) II C) III D) IV E) V$

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C

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A

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1,2-product is the major one ...
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A

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