Deck 19: Radicals

Question 1

What is the major product of the reaction shown below?

A)
B)
C)
D)

Answer 1

Question 2

What reagent or condition is missing in the following reaction scheme?

A)ROOR
B)H₃O⁺
C)Heat
D)hv

Answer 2

hv

Question 3

What accounts for the regioselectivity of radical halogen?

A)More substituted carbons have lower C-H bond disassociation energies than less substituted carbons.
B)More substituted carbons have higher C-H bond disassociation energies than less substituted carbons.
C)More substituted carbons have lower C-X bond disassociation energies than less substituted carbons,where X represents a halide.
D)More substituted carbons have higher C-X bond disassociation energies than less substituted carbons,where X represents a halide.

Answer 3

More substituted carbons have lower C-H bond disassociation energies than less substituted carbons.

Question 4

What kind of polymerization reaction is shown below?

A)alkenyl
B)polar
C)addition
D)condensation

Question 5

Which of the following terms best describes radical bond breakage?

A)homolytic cleavage
B)heterolytic cleavage
C)polar cleavage
D)non-polar cleavage

Question 6

What monomer subunit would form the addition polymer shown below?

A)
B)
C)
D)

Question 7

Which of the following conditions would accomplish the transformation shown below?

A)Zn/Hg,HCl
B)Zn/Hg,NaOH
C)1)LiAlH4,2)H₃O⁺
D)1)LiAlH4,2)NaOH

Question 8

Which of the following represents a radical propagation step?

A)
B)
C)
D)

Question 9

What is the major product of the transformation shown below?

A)
B)
C)
D)

Question 10

Which of the following represents a radical termination step?

A)
B)
C)
D)

Question 11

Which of the following represents a radical initiation step?

A)
B)
C)
D)

Question 12

What is the major product of the transformation shown below?

A)
B)
C)
D)

Question 13

What is the product of the reaction shown below?

A)
B)
C)
D)

Question 14

What is the major product of the transformation shown below?

A)
B)
C)
D)

Question 15

Which of the following best describes a radical bromination reaction?

A)Markovnikov regiochemistry
B)anti-Markovnikov regiochemistry
C)Markovnikov stereochemistry
D)anti-Markovnikov stereochemistry

Question 16

Which of the following represents the most stable radical?

A)
B)
C)
D)

Question 17

Which of the following represents the most stable radical?

A)
B)
C)
D)

Question 18

Which of the following represents the most stable radical?

A)
B)
C)
D)

Question 19

What is the major product of the reaction shown below?

A)
B)
C)
D)

Question 20

What is the role of ammonia in the mechanism of the Birch reduction shown below?

A)stoichiometric acid
B)stoichiometric base
C)catalytic acid
D)catalytic base

Question 21

Birch reduction of an alkyne results in a cis-alkene.

Question 22

Which of the following would produce the least stable radical?

A)
B)
C)
D)

Question 23

Which of the following hydrocarbons would produce the most stable radical?

A)
B)
C)
D)

Question 24

Which of the following reagents would achieve the transformation shown below?

A)Na/NH₃ (l)
B)AlBN,HSnBu₃
C)Zn/Hg,HCl
D)hv ROOR

Question 25

What role do radicals play in a radical initiation reaction?

A)They are reactants only.
B)They are products only.
C)They are both reactants and products.
D)They are neither reactants nor products.

Question 26

Which of the following would produce the most stable radical?

A)
B)
C)
D)

Question 27

What monomer subunit would form the addition polymer shown below?

A)
B)
C)
D)

Question 28

Which of the following represents the first mechanistic step of the aromatic reduction shown below?

A)
B)
C)
D)

Question 29

Which of the following reagents would achieve the transformation shown below?

A)Na/NH₃ (l)
B)AlBN,HSnBu₃
C)Zn/Hg,HCl
D)hv,ROOR

Question 30

What monomer subunit would form the addition polymer shown below?

A)
B)
C)
D)

Question 31

Radical propagation reactions involve radical reactants and products.

Question 32

What role do radicals play in a radical termination reaction?

A)They are reactants only.
B)They are products only.
C)They are both reactants and products.
D)They are neither reactants nor products.

Question 33

Termination of a radical cycle involves a bond being formed from two radicals.

Question 34

What role do radicals play in a radical propagation reaction?

A)They are reactants only.
B)They are products only.
C)They are both reactants and products.
D)They are neither reactants nor products.

Question 35

Radical chlorination is more regioselective than radical bromination.

Question 36

Which of the following best describes the conditions required to generate radicals?

A)heat
B)UV light
C)rigorous mixing
D)both heat and UV light

Question 37

Tertiary radicals are less stable than secondary radicals.

Question 38

Which of the following best describes stabilization of radicals?

A)Radicals are stabilized by electron delocalization but not hyperconjugation.
B)Radicals are stabilized by hyperconjugation but not electron delocalization.
C)Radicals are stabilized by both electron delocalization and hyperconjugation.
D)Radicals are stabilized by neither electron delocalization nor hyperconjugation.

Question 39

A stochiometric amount of radical imitator is required for radical reactions.

Question 40

Adjacent electronegative atom with lone pair electrons help stabilize radicals.

Question 41

Electron-withdrawing groups affect the regiochemistry of the Birch reduction.

Question 42

The Birch reduction involves the transformation of aromatic species into a 1,3-cyclohexadienes.

Question 43

Radical bromination has _______________ regiochemistry

Question 44

In radical additions of HBr with alkenes,peroxides act as a radical initiator

Question 45

Secondary alkyl halides are formed preferentially over primary alkyl halides in radical halogenations.

Question 46

Fishhook arrows are representative of homolytic cleavage.

Question 47

Electrons solvated in ammonia have a characteristic blue colour.

Question 48

In the Birch reduction,magnesium metal is oxidized to produce solvated electrons.

Question 49

Carbon radicals are sp² hybridized.

Question 50

Radicals are stabilized by delocalization.

Question 51

AIBN is used as a radical initiator in dehalogenation of alkyl halides.

Question 52

Reduction of an alkyne with dissolved sodium metal in ammonia results in a(n)_______________ geometry alkene

Question 53

A zinc/mercury alloy is used in the reduction of carbonyls.

Question 54

Electrons are solvated in aqueous solutions for their use in metal reduction reactions.

Question 55

The Clemmensen reduction results in the reduction of a ketone to an alcohol.

Question 56

Dissolving metal reduction of alkynes results in a trans alkene.

Question 57

Primary radicals are less stable than tertiary radicals.

Question 58

Radical addition of hydrogen bromide to an alkene leads to a Markovnikov product.

Question 59

NBS is used for allylic halogenation.

Question 60

Tributyl tin hydride is used as a radical initiator in dehalogenation of alkyl halides.

Question 61

Show the mechanism for the three stages (initiation,propagation,and termination)of the following radical reaction.

Question 62

Fishhook arrows are involved in _______________ cleavage.

Question 63

In radical reactions,peroxides tend to act as _______________ .

Question 64

What is the major product of the reaction shown below?

Question 65

In the radical addition of HBr to an alkene,a peroxide acts as a(n)_______________ .

Question 66

Draw the mechanism of the following dissolving metal transformation.

Question 67

What is the product of the following reaction?

Question 68

_______________ cleavage represents a bond-breaking reaction where both electrons migrate to one atom.

Question 69

The formation of a sigma bond from two radicals represents a(n)_______________ step in a radical chain reaction.

Question 70

Predict the product of the following addition polymerization reaction.

Question 71

Propose a mechanism for the following transformation.

Question 72

The Birch reduction involves transforming a(n)_______________ into a 1,4-cyclohexadiene.

Question 73

Draw the possible products of the reaction shown below.Indicate the major product.

Question 74

Solvated electrons in ammonia result in a deep _______________ colour.

Question 75

The three phases of a radical chain reaction are initiation,_______________ ,and termination.

Question 76

What reactant would form the product shown below?