Question 1

Which of the following isnot a correct designation for a sigmatropic rearrangement?

Accepted Answer

A)   [3,3]
B)   [1,3]
C)   [3,1]
D)   [1,5]E) A) and C)
F) B) and D)

Question 2

Which of the following polymers can be made at least in part from glucose derived from a renewable plant source?

Accepted Answer

A)   Sorona
B)   Polypropylene
C)   Polyethylene
D)   TeflonE) A) and D)
F) A) and C)

Question 3

What type of sigmatropic rearrangement is illustrated below?

Accepted Answer

A)   [1,5]
B)   [1,3]
C)   [1,4]
D)   [3,3]E) B) and D)
F) All of the above

Question 4

Why is the Diels-Alder reaction called a thermal [4+2] cycloaddition?

Accepted Answer

A)   Because the reaction is initiated by light; the dienophile has fourp electrons and the diene has twop electrons.
B)   Because the reaction is initiated by heat; the diene has fourp electrons and the dienophile has twop electrons.
C)   Because the reaction is initiated by light; the diene has fourp electrons and the dienophile has twop electrons.
D)   Because the reaction is initiated by heat; the dienophile has fourp electrons and the diene has twop electrons.E) B) and D)
F) C) and D)

Question 5

Which of the following statements about ap-bonding molecular orbital is true?

Accepted Answer

A)   Ap-bonding molecular orbital is formed when twop orbitals of opposite phase overlap.
B)   Ap-bonding molecular orbital is lower in energy than as-bonding molecular orbital.
C)   Both the statements ap-bonding molecular orbital is formed when twop orbitals of similar phase overlap and ap-bonding molecular orbital is lower in energy than as-bonding molecular orbital are true.
D)   Ap-bonding molecular orbital is formed when twop orbitals of similar phase overlap.E) C) and D)
F) A) and C)

Question 6

Consider the following reaction sequence. What is the correct classification of the first reaction in the sequence?

Accepted Answer

A)   [3,3] Sigmatropic rearrangement
B)   [1,3] Sigmatropic rearrangement
C)   [1,5] Sigmatropic rearrangement
D)   [5,5] Sigmatropic rearrangementE) A) and D)
F) A) and C)

Question 7

Which of the following statements about the Cope rearrangement isnot true?

Accepted Answer

A)   The Cope rearrangement involves the rearrangement of a 1,5-diene to an isomeric 1,5-diene.
B)   The Cope rearrangement takes place readily in a suprafacial pathway under photochemical conditions.
C)   The Cope rearrangement involves three electron pairs; two inp bonds and one in as bond.
D)   The Cope rearrangement takes place readily in a suprafacial pathway, when heated.E) B) and C)
F) None of the above

Question 8

Which of the following statements about ap* antibonding molecular orbital is true?

Accepted Answer

A)   Ap* antibonding molecular orbital is formed when twop orbitals of similar phase overlap.
B)   Both the statements ap* antibonding molecular orbital is formed when twop orbitals of opposite phase overlap and ap* antibonding molecular orbital is a higher-energy molecular orbital than ap bonding molecular orbital are true.
C)   Ap* antibonding molecular orbital is formed when twop orbitals of opposite phase overlap.
D)   Ap* antibonding molecular orbital is a higher-energy molecular orbital than ap bonding molecular orbital.E) B) and D)
F) B) and C) B

Question 9

Which of the following statements about sigmatropic reactions isnot true?

Accepted Answer

A)   Thep bonds rearrange in a sigmatropic reaction.
B)   A sigmatropic reaction is an intramolecular pericyclic reaction.
C)   In a sigmatropic reaction,s bond is broken in one of the reactants.
D)   The number ofp bonds in the reactants and product differs in a sigmatropic reaction.E) B) and C)
F) A) and D)

Question 10

Which of the following statements about an electrocyclic ring-opening reaction isnot true?

Accepted Answer

A)   The product of an electrocyclic ring-opening reaction contains one fewerp bond than the reactant.
B)   The product of an electrocyclic ring-opening reaction contains one morep bond than the reactant.
C)   An electrocyclic ring-opening reaction requires a source of energy (heat or light) .
D)   An electrocyclic ring-opening reaction is an intramolecular reaction.E) A) and B)
F) None of the above A

Question 11

Which of the following statements about the Claisen rearrangement is true?

Accepted Answer

A)   The Claisen rearrangement occurs readily in a suprafacial pathway under photochemical conditions.
B)   The Claisen rearrangement involves three electron pairs; two inp bonds and one in as bond.
C)   The Claisen rearrangement occurs readily in an antarafacial pathway under thermal conditions.
D)   The Claisen rearrangement involves the rearrangement of an unsaturated ether to a b,g-unsaturated carbonyl compound.E) B) and C)
F) All of the above

Question 12

Which of the following statements about thermal electrocyclic reactions isnot true?

Accepted Answer

A)   The number ofs bonds in the conjugated polyene determines whether rotation is conrotatory or disrotatory.
B)   In thermal reactions, we consider the orbitals of the HOMO of the ground state electronic configuration to determine the course of the reaction.
C)   Thermal electrocyclic reactions occur in a conrotatory fashion for a conjugated polyene with an even number ofp bonds.
D)   Thermal electrocyclic reactions occur in a disrotatory fashion for a conjugated polyene with an odd number ofp bonds.E) None of the above
F) A) and D)

Question 13

Which of the following polymers can be recycled into floor mats?

Accepted Answer

A)   LDPE
B)   PVC
C)   HDPE
D)   PETE) A) and B)
F) A) and C)

Question 14

What type of sigmatropic rearrangement is illustrated below?

Accepted Answer

A)   [3,3]
B)   [1,4]
C)   [1,5]
D)   [1,3]E) A) and D)
F) B) and C) D

Question 15

What type of sigmatropic rearrangement is illustrated below?

Accepted Answer

A)   [1,3]
B)   [1,4]
C)   [1,5]
D)   [3,3]E) B) and C)
F) A) and D)

Question 16

Bakelite is formed by the acid-catalyzed polymerization of phenol with formaldehyde. What is (are)  the product(s)  of the first step in this polymerization, shown below? (Note: in the answers below the hydroxymethyl group is -CH2OH.)  2OH.)    A)  Ortho andpara-hydroxybenzaldehyde B)  Meta-(hydroxymethyl) phenol C)  Ortho andpara-(hydroxymethyl) phenol D)  Meta-hydroxybenzaldehyde" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   Ortho andpara-hydroxybenzaldehyde
B)   Meta-(hydroxymethyl) phenol
C)   Ortho andpara-(hydroxymethyl) phenol
D)   Meta-hydroxybenzaldehydeE) A) and C)
F) B) and D)

Question 17

Which of the following statements about cycloaddition reactions isnot true?

Accepted Answer

A)   Cycloaddition reactions are stereospecific.
B)   Cycloaddition reactions are concerted.
C)   The course of the reaction is determined by the symmetry of the molecular orbitals of the products.
D)   Cycloaddition reactions form a cyclic product with two news bonds.E) B) and C)
F) All of the above

Question 18

Which of the following statements about orbital symmetry and cycloaddition reactions is true?

Accepted Answer

A)   Thermal cycloadditions involving an odd number ofp bonds proceed by an antarafacial pathway.
B)   Thermal cycloadditions involving an even number ofp bonds proceed by a suprafacial pathway.
C)   Photochemical cycloadditions involving an even number ofp bonds proceed by an antarafacial pathway.
D)   Photochemical cycloadditions involving an even number ofp bonds proceed by a suprafacial pathway.E) C) and D)
F) B) and C)

Question 19

Which of the following statements about photochemical electrocyclic reactions isnot true?

Accepted Answer

A)   Photochemical electrocyclic reactions occur in a disrotatory fashion for a conjugated polyene with an even number ofp bonds.
B)   Photochemical electrocyclic reactions occur in a conrotatory fashion for a conjugated polyene with an odd number ofp bonds.
C)   In photochemical reactions, we consider the orbitals of the HOMO of the excited state to determine the course of the reaction.
D)   In photochemical reactions, we consider the orbitals of the LUMO of the excited state to determine the course of the reaction.E) A) and B)
F) A) and C)

Question 20

Which of the following statements about orbital symmetry and cycloaddition reactions is true?

Accepted Answer

A)   Photochemical sycloadditions involving an even number ofp bonds proceed by an antarafacial pathway.
B)   Photochemical cycloadditions involving an odd number ofp bonds proceed by a suprafacial pathway.
C)   Thermal cycloadditions involving an even number ofp bonds proceed by a suprafacial pathway.
D)   Thermal cycloadditions involving an odd number ofp bonds proceed by a suprafacial pathway.E) A) and C)
F) C) and D)

Exam 28: Pericyclic Reactions, and Synthetic Polymers

Which of the following isnot a correct designation for a sigmatropic rearrangement?

Correct AnswerverifiedShow Answer

Which of the following polymers can be made at least in part from glucose derived from a renewable plant source?

Correct AnswerverifiedShow Answer

What type of sigmatropic rearrangement is illustrated below?

Correct AnswerverifiedShow Answer

Why is the Diels-Alder reaction called a thermal [4+2] cycloaddition?

Correct AnswerverifiedShow Answer

Which of the following statements about ap-bonding molecular orbital is true?

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Consider the following reaction sequence. What is the correct classification of the first reaction in the sequence?

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Which of the following statements about the Cope rearrangement isnot true?

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Which of the following statements about ap* antibonding molecular orbital is true?

Correct AnswerverifiedB

Which of the following statements about sigmatropic reactions isnot true?

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Which of the following statements about an electrocyclic ring-opening reaction isnot true?

Correct AnswerverifiedA

Which of the following statements about the Claisen rearrangement is true?

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Which of the following statements about thermal electrocyclic reactions isnot true?

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Which of the following polymers can be recycled into floor mats?

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What type of sigmatropic rearrangement is illustrated below?

Correct AnswerverifiedD

What type of sigmatropic rearrangement is illustrated below?

Correct AnswerverifiedShow Answer

Bakelite is formed by the acid-catalyzed polymerization of phenol with formaldehyde. What is (are) the product(s) of the first step in this polymerization, shown below? (Note: in the answers below the hydroxymethyl group is -CH2OH.)

Correct AnswerverifiedShow Answer

Which of the following statements about cycloaddition reactions isnot true?

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Which of the following statements about orbital symmetry and cycloaddition reactions is true?

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Which of the following statements about photochemical electrocyclic reactions isnot true?

Correct AnswerverifiedShow Answer

Which of the following statements about orbital symmetry and cycloaddition reactions is true?

Correct AnswerverifiedShow Answer

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B

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A

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D

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Bakelite is formed by the acid-catalyzed polymerization of phenol with formaldehyde. What is (are) the product(s) of the first step in this polymerization, shown below? (Note: in the answers below the hydroxymethyl group is -CH₂OH.)

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