Deck 10: Radical Reactions

Question 1

As the term "peroxide" is used in Chapter 10,it can refer to which structure(s)?

A)ROOR
B)ROOH
C)
D)Two of these choices.
E)Three of these choices.

Answer 1

Three of these choices.

Question 2

Which of these molecules is not expected to arise as a product of the high temperature chlorination of methane?

A)CCl₄
B)HCCl₃
C)CH₂Cl₂
D)CH₃CH₃
E)CH₂=CH₂

Answer 2

CH₂=CH₂

Question 3

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Answer 3

III

Question 4

In the presence of light,ethane (1 mol)reacts with chlorine (1 mol)to form which product(s)?

A)CH₂ClCHCl₂
B)CH₃CHCl₂
C)CH₃CH₂Cl
D)ClCH₂CH₂Cl
E)All of these choices.

Question 5

In a competition reaction,equimolar amounts of five alkanes compete for a deficiency of chlorine at 300 °C.The greatest amount of reaction would occur in the case of which of these alkanes?

A)Ethane
B)Propane
C)Butane
D)Isobutane
E)Pentane

Question 6

Free radicals can be produced by:

A)use of high temperatures.
B)irradiation with light.
C)reaction of a molecule with another free radical.
D)both use of high temperatures and irradiation with light.
E)use of high temperatures,irradiation with light,and reaction of a molecule with another free radical.

Question 7

Which of the following gas-phase reactions is a possible chain-terminating step in the light-initiated chlorination of methane?

A)Cl-Cl $\to$ 2Cl·
B)Cl· + CH₄ $\to$ CH₃· + H-Cl
C)CH₃· + CH₃· $\to$ CH₃-CH₃
D)CH₃· + Cl-Cl $\to$ CH₃Cl + Cl·
E)More than one of these choices.

Question 8

What feature would you expect to see in the ¹H NMR spectrum of B after subjecting A to the following reaction?

A)There would be only 4 aromatic protons at low field.
B)The signal for the protons on the benzylic carbon would be a doublet.
C)The signal for the methyl protons would be a triplet.
D)The signal for the methyl protons would be a doublet.
E)The signal for the methyl protons would integrate for only 2 hydrogens.

Question 9

The reaction of 2-methylbutane with chlorine and light would yield how many monochloro derivatives? (include stereoisomers)

A)2
B)3
C)4
D)5
E)6

Question 10

What sequence of reactions could be used to prepare cis-1,2-cyclopentanediol from cyclopentane?

A)(1)Cl₂,h $v$ ; (2)t-BuOK/t-BuOH; (3)OsO₄; (4)NaHSO₃/H₂O
B)(1)t-BuOK/t-BuOH; (2)Cl₂,h $v$ ; (3)NaOH/H₂O
C)(1)Cl₂,h $v$ ; (2)t-BuOK/t-BuOH; (3)H₂O₂
D)(1)NaOH/H₂O; (2)Br₂; (3)NaNH₂ (2 eq.)/liq.NH₃; (4)KMnO₄,NaOH/H₂O,5 °C
E)(1)Cl₂,h $v$ ; (2)t-BuOK/t-BuOH; (3)Hg(OAc)₂,H₂O (4)NaBH₄,H₃O⁺

Question 11

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Question 12

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Question 13

In the presence of light at 25 °C,isobutane (1 mol)and bromine (1 mol)yield which monobromo product(s)?

A)2-Methyl-1-bromopropane (almost exclusively)
B)2-Methyl-2-bromopropane (almost exclusively)
C)A mixture of 50% (A)and 50% (B)
D)A mixture of 90% (A)and 10% (B)
E)Butyl bromide

Question 14

How many different monochlorobutanes (including stereoisomers)are formed in the free radical chlorination of butane?

A)1
B)2
C)3
D)4
E)5

Question 15

Select the structure of the major product formed in the following reaction.

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

Question 16

At some temperatures,the relative reactivities of 3°,2° and 1° alkane hydrogens in free radical chlorination are in the ratio of 5:3:1.Thus,monochlorination of isopentane should produce these percentages of 2-chloro-2-methylbutane (A),combined 1-chloro-2-methylbutane and 1-chloro-3-methylbutane (B),and 2-chloro-3-methylbutane (C):

A)8% A,75% B,17% C
B)25% A,45% B,30% C
C)29% A,44% B,18% C
D)30% A,35% B,35% C
E)36% A,43% B,21% C

Question 17

Hydrogen atom abstraction from which position would yield the most stable free radical intermediate during the reaction of bromine with 2,2,3-trimethylpentane?

A)C1
B)C2
C)C3
D)C4
E)C5

Question 18

Which of the following free radicals is the most stable?

A)
B)
C)
D)
E)

Question 19

A chain reaction is one that:

A)involves a series of steps.
B)involves two steps of equal activation energy.
C)is one that can be initiated by light.
D)involves a series of steps,each of which generates a reactive intermediate that brings about the next step.
E)involves free radicals that have an unusual stability and thereby cause a large quantum yield.

Question 20

If chlorocyclopentane were chlorinated to form all possible dichloro compounds and the product mixture subjected to precise fractional distillation,how many fractions would be obtained (ideally)?

A)3
B)4
C)5
D)7
E)9

Question 21

Which of the following would be the major product in the following reaction sequence?

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

Question 22

Which hydrogen would be abstracted first when mono-brominating with Br₂ and light?

A)Ha
B)Hb
C)Hc
D)Hd
E)He

Question 23

Which hydrogen would be abstracted first when mono-brominating with Br₂ and light?

A)H_a
B)H_b
C)H_c
D)H_d
E)H_e

Question 24

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Question 25

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Question 26

Which hydrogen would be abstracted first when mono-brominating with Br₂ and light?

A)H_a
B)H_b
C)H_c
D)H_d
E)H_e

Question 27

What is the product for the following three-step reaction sequence?

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

Question 28

Which hydrogen would be abstracted first when mono-brominating with Br₂ and light?

A)H_a
B)H_b
C)H_c
D)H_d
E)H_e

Question 29

What would be the major product of the following reaction sequence?

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

Question 30

What is the product for the following three-step reaction sequence?

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

Question 31

What would be the major product of the following reaction sequence?

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

Question 32

What would be the major product of the following reaction sequence?

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

Question 33

Mono-bromination of the following alkane, ,(using Br₂ with light)would give?

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

Question 34

What would be the major product of the following reaction sequence?

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

Question 35

Which hydrogen would be abstracted first when mono-brominating with Br₂ and light?

A)H_a
B)H_b
C)H_c
D)H_d
E)H_e

Question 36

What would be the major product of the following reaction sequence?

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

Question 37

Which of the following would be the major product in the following reaction sequence?

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

Question 38

Free radical mono-halogenation of an alkane is typically conducted using bromine versus chlorine because

A)the bromine radical is more reactive and therefore more selective.
B)the chlorine radical is more reactive and therefore more selective.
C)the chlorine radical is less reactive and therefore more selective.
D)the bromine radical is less reactive and therefore more selective.
E)None of these choices.

Question 39

What is the product for the following reaction sequence?

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

Question 40

Which statement best describes the reaction of bromine with isobutane?

A)Bromine radical selectively abstracts the tertiary hydrogen.
B)The transition state of the rate determining step is product-like.
C)The major product formed from this reaction is 1-bromo-2-methylpropane.
D)Bromine radical selectively abstracts the tertiary hydrogen and the transition state of the rate determining step is product-like.
E)Bromine radical selectively abstracts the tertiary hydrogen,the transition state of the rate determining step is product-like,and the major product formed from this reaction is 1-bromo-2-methylpropane.

Question 41

The p orbital of a methyl radical carbon,CH₃·,contains how many electrons?

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

Question 42

The hybridization state of the carbon of a methyl radical is:

A)sp
B)sp²
C)sp³
D)sp⁴
E)p³

Question 43

What is the major product obtained from the following reaction sequence?

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

Question 44

Which of the following would be the major product in the following reaction sequence?

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

Question 45

Free radical chlorination will produce but one monochloro derivative in the case of:

A)Propane
B)Butane
C)Isobutane
D)Isopentane
E)Neopentane

Question 46

The reaction of 2,2-dimethylbutane with chlorine would yield how many monochloro derivatives? (include stereoisomers)

A)1
B)2
C)3
D)4
E)5

Question 47

What is the total number of trichloropropanes which can be produced by free radical chlorination of propane? Include all stereoisomers.

A)4
B)5
C)6
D)7
E)8

Question 48

Free radical chlorination of hexane produces this number of monochloro derivatives (including stereoisomers):

A)3
B)4
C)5
D)7
E)8

Question 49

The free radical chlorination of pentane produces this number of monochloro compounds,including stereoisomers.

A)2
B)3
C)4
D)5
E)6

Question 50

How many monochloro derivatives,including stereoisomers,can be formed in the chlorination of 1-bromobutane?

A)4
B)5
C)6
D)7
E)8

Question 51

More than one monochloro compound can be obtained from the free radical chlorination of:

A)Cyclopentane
B)Neopentane
C)Isobutane
D)Ethane
E)Methane

Question 52

What is the product for the following three-step reaction sequence?

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

Question 53

What is the product for the following three-step reaction sequence?

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

Question 54

What is the product for the following three-step reaction sequence?

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

Question 55

The reaction between cyclopropane and one equivalent of bromine when exposed to light would yield how many different compounds (including stereoisomers)?

A)1
B)2
C)3
D)4
E)5

Question 56

What is the product for the following three-step reaction sequence?

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

Question 57

The free radical chlorination of (R)-2-chloropentane forms a mixture of dichloropentanes which includes:

A)three optically active compounds.
B)two achiral compounds.
C)two meso compounds.
D)one pair of diastereomers.
E)one racemic mixture.

Question 58

What is the product for the following three-step reaction sequence?

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

Question 59

What is the final product,C,obtained via the following reaction sequence?

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

Question 60

Which of the following would be the major product in the following reaction sequence?

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

Question 61

Which would be the best synthesis to produce the vicinal dibromide?

A)
B)
C)
D)
E)

Question 62

Which free radical would be least stable?

A)
B)
C)
D)
E)

Question 63

Which carbon of is predicted to be the major site of substitution when this alkene reacts with chlorine at 400 ^$\circ$ C?

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

Question 64

Which hydrogen atom(s)of is/are most susceptible to abstraction by free radicals?

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

Question 65

What would be the major product of the following reaction sequence?

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

Question 66

Which free radical would be most stable?

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

Question 67

Which hydrogen atom(s)of is/are least susceptible to abstraction by free radicals?

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

Question 68

Which of the following would be the major product in the following reaction sequence?

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

Question 69

Which of the following compounds is not formed as a result of a chain-termination step in the free radical chlorination of propene?

A)CH₂=CHCH₂Cl
B)Cl₂
C)CH₂=CHCH₂CH₂CH=CH₂
D)HCl
E)All can be formed in chain-termination steps.

Question 70

Which free radical would be most stable?

A)
B)
C)
D)
E)

Question 71

The free radical chlorination of 3-chloropentane forms a mixture of dichloropentanes which,on precise fractional distillation,affords these fractions:

A)4 fractions,none optically active
B)4 fractions,2 optically active
C)7 fractions,4 optically active
D)7 fractions,6 optically active
E)7 fractions,all optically active

Question 72

An unsaturated product results from the reaction of cyclohexene with which of these?

A)Br₂/CCl₄ at 25 ^$\circ$ C
B)NBS/CCl₄,ROOR
C)HCl,ROOR
D)HCl,no peroxides
E)More than one of these choices.

Question 73

What would be the major product of the following reaction sequence?

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

Question 74

Which set of conditions does not result in allylic halogenation of an alkene?

A)Cl₂ at 400 ^$\circ$ C
B)Cl₂ in CCl₄ at 25 ^$\circ$ C
C)Cl₂,ROOR,h $v$
D)Br₂ at low concentration in CCl₄
E)N-Bromosuccinimide in CCl₄,ROOR

Question 75

Consider the light-initiated chlorination of (S)-2-chlorobutane followed by careful fractional distillation (or separation by GLC)of all of the products with the formula C₄H₈Cl₂.How many fractions (in total)would be obtained and how many of these fractions would be optically active?

A)Three fractions total; all optically active
B)Four fractions total; three fractions optically active
C)Five fractions total; all optically active
D)Five fractions total; four fractions optically active
E)Five fractions total; three fractions optically active

Question 76

What would be the major product of the following reaction sequence?

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

Question 77

Which of the following would be the major product in the following reaction sequence?

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

Question 78

Which hydrogen atom(s)of is/are most susceptible to abstraction by free radicals?

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

Question 79

Which free radical would be most stable?

A)
B)
C)
D)
E)

Question 80

Which free radical would be least stable?

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