Deck 8: Haloalkanes, Halogenation, and Radical Reactions

Question 1

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

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

Answer 1

2

Question 2

What is the correct order of stability of the following radicals (more stable > less stable)?

A) 1 > 2 > 3
B) 1 > 3 > 2
C) 3 > 1 > 2
D) 3 > 2 > 1

Answer 2

3 > 2 > 1

Question 3

Which of the following statements is not true?

A) homolytic cleavage of a bond in a neutral molecule gives two radicals
B) radicals have one or more unpaired electrons
C) movement of single electrons is depicted using a "fishhook arrow"
D) the C-F bond is the weakest bond between carbon atom and a halogen

Answer 3

the C-F bond is the weakest bond between carbon atom and a halogen

Question 4

Which of the following has the list of compounds in the correct order of decreasing boiling point (higher boiling point > lower boiling point)?

A) 2-fluoropropane > 2-chloropropane > 2-bromopropane > 2-iodopropane
B) 2-chloropropane > 2-iodopropane > 2-fluoropropane > 2-bromopropane
C) 2-iodopropane > 2-chloropropane > 2-fluoropropane > 2-bromopropane
D) 2-iodopropane > 2-bromopropane > 2-chloropropane > 2-fluoropropane

Question 5

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

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

Question 6

Which of the following has the list of compounds in the correct order of decreasing boiling point (higher boiling point > lower boiling point)?

A) chloromethane > chloroethane > 2-chloropropane > 2-chloro-2-methylpropane
B) 2-chloro-2-methylpropane > 2-chloropropane > chloroethane > chloromethane
C) chloroethane > chloromethane > 2-chloro-2-methylpropane > 2-chloropropane
D) chloromethane > 2-chloro-2-methylpropane > 2-chloropropane > chloroethane

Question 7

What is the correct assignment of the names of the following compounds?

A) 1 = methyl chloride; 2 = chloroform; 3 = methylene chloride
B) 1 = trichlor; 2 = chloroform; 3 = methylene chloride
C) 1 = methyl chloride; 2 = methylene chloride; 3 = chloroform
D) 1 = chloroform; 2 = methylene chloride; 3 = trichlor

Question 8

Which of the following has the list of compounds in the correct order of decreasing polarity (more polar > less polar)?

A) CCl₄ > CHCl₃ > CH₂Cl₂
B) CH₂Cl₂ > CHCl₃ > CCl₄
C) CCl₄ > CH₂Cl₂ > CHCl₃
D) CHCl₃ > CCl₄ > CH₂Cl₂

Question 9

Which of the following has the list of compounds in the correct order of decreasing density (higher density > lower density)?

A) CH₂Cl₂ > CH₂Br₂ > CH₂I₂
B) CH₂Cl₂ > CH₂I₂ > CH₂Br₂
C) CH₂I₂ > CH₂Br₂ > CH₂Cl₂
D) CH₂I₂ > CH₂Cl₂ > CH₂Br₂

Question 10

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

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

Question 11

What is the IUPAC name of the following compound?

A) (R)-2-bromo-2-vinylpentane
B) (S)-2-bromo-2-vinylpentane
C) (S)-3-bromo-3-propyl-1-butene
D) (R)-3-bromo-3-methyl-1-hexene

Question 12

Which halogen is most useful in the regioselective radical halogenation of alkenes??

A) fluorine
B) chlorine
C) bromine
D) iodine

Question 13

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

A) 1 and 2
B) 3 and 4
C) 1 and 3
D) 2 and 4

Question 14

Which of the following bonds has the lowest bond dissociation enthalpy?

A) C-H
B) C-F
C) C-Br
D) C-I

Question 15

What is the characteristic of a radical chain propagation step?

A) radicals are formed
B) byproducts are formed
C) a radical reacts with a molecule to give a new radical and a new molecule
D) two radicals combine to give a molecule

Question 16

What is the correct order of stability of the following radicals (more stable > less stable)?

A) 1 > 2 > 3
B) 2 > 1 > 3
C) 2 > 3 > 1
D) 3 > 2 > 1

Question 17

What is the IUPAC name of the following compound?

A) (E)-1-chloro-1,2,3-trimethyl-1-butene
B) (Z)-1-chloro-1,2,3-trimethyl-1-butene
C) (E)-2-chloro-3,4-dimethyl-2-pentene
D) (Z)-2-chloro-3,4-dimethyl-2-pentene

Question 18

What is the characteristic of a radical chain initiation step?

A) radicals are formed
B) substitution products are formed
C) a radical reacts with a molecule to give a new radical and a new molecule
D) two radicals combine to give a molecule

Question 19

What is the IUPAC name of the following compound?

A) (R)-1-chloro-3-methyl-2-cyclohexene
B) (S)-1-chloro-3-methyl-2-cyclohexene
C) (R)-3-chloro-1-methylcyclohexene
D) (S)-3-chloro-1-methylcyclohexene

Question 20

Which of the following has the list of compounds in the correct order of decreasing molecular polar (more polar > less polar)?

A) CH₃I > CH₃Br > CH₃Cl > CH₃F
B) CH₃F > CH₃Cl > CH₃Br > CH₃I
C) CH₃Cl > CH₃F > CH₃Br > CH₃I
D) CH₃Cl > CH₃I > CH₃F > CH₃Cl

Question 21

How many p-bonding, non-bonding, and antibonding orbitals does the allyl radical possess?

A) one bonding, one nonbonding, and one antibonding
B) two bonding, no nonbonding, and no antibonding
C) two bonding, one nonbonding, and no antibonding
D) three bonding, no nonbonding, and no antibonding

Question 22

What is the major product of autooxidation of cyclohexene?

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

Question 23

What type of orbital contains the unpaired electron of the tert-butyl radical?

A) s
B) p
C) sp³
D) sp

Question 24

Which of the following is an accurate statement of Hammond's postulate?

A) the transition state of an exothermic reaction will resemble the starting materials (reactants) more than the product
B) the transition state of an exothermic reaction will resemble the products more than the starting materials (reactants)
C) the transition state of an endothermic reaction will resemble the starting materials (reactants) more than the product
D) the difference in energy between the starting materials (reactants) and transition state controls the rate of a reaction

Question 25

How many electrons does the allyl radical have in p orbitals

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

Question 26

Which of the following alkenes undergoes allylic bromination to form a single monobrominated product?

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

Question 27

Which of the following statements is not true?

A) Bromine radicals add to the least substituted end of a carbon-carbon double bond of an alkene.
B) The major anti-Markovnikov product obtained upon addition of HBr to alkenes in the presence of a peroxide is formed in a radical termination step.
C) Two radicals combine in radical termination steps.
D) Alkoxy radicals remove a hydrogen atom from HBr to give an alcohol and a bromine atom.

Question 28

What type of reactive intermediate is formed upon irradiation of a solution of toluene (Ph-CH₃) and bromine?

A) benzylic carbocation
B) benzylic carbanion
C) benzylic radical
D) cyclic bromonium ion

Question 29

Which of the following compounds is most susceptible to autooxidation?

A) propene
B) 1,3-butadiene
C) 1,4-pentadiene
D) 1,5-hexadiene

Question 30

Which of the following statements is not true regarding the halogenation of alkanes upon treatment with halogen and light?

A) bromination is more selective for 3 $\degree$ positions than chlorination
B) the reaction proceeds via a radical intermediate
C) the reaction proceeds via a chain reaction
D) this is a useful process for the formation of fluorides, chlorides, bromides and iodides

Question 31

What is the major product obtained from the reaction of 2-methyl-2-butene with hydrogen bromide in the presence of peroxides?

A) 2,3-dibromo-2-methylbutane
B) 2-bromo-3-methylbutane
C) 2-bromo-2-methylbutane
D) (E)-1-bromo-2-methyl-2-butene

Question 32

What is the major product formed upon radical bromination of (S) 3-methylhexane?

A) (S) 3-bromo-3-methylhexane
B) (R) 3-bromo-3-methylhexane
C) a mixture of (R) and (S) 3-bromo-3-methylhexane
D) (3R) 1-bromo-3-methylhexane

Question 33

What type of orbitals overlap to provide stability to the tert-butyl radical by hyperconjugation?

A) 3 $\degree$ C 2p atomic orbital + 3 $\degree$ C sp² atomic orbital
B) 3 $\degree$ C 2p atomic orbital + methyl C-H s molecular orbital
C) 3 $\degree$ C sp² atomic orbital + methyl C-H s molecular orbital
D) 3 $\degree$ C 2p atomic orbital + methyl C 2s atomic orbital

Question 34

What type of reactive intermediate is formed in the reaction of propene with hydrogen bromide in the presence of peroxides to give 1-bromopropane?

A) 1 $\degree$ radical
B) 1 $\degree$ carbocation
C) 1 $\degree$ radical.
D) 2 $\degree$ radical

Question 35

Which of the following alkanes does not undergo monobromination to form a single bromoalkane as the major product?

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

Question 36

What is the geometry of the central carbon atom of a tert-butyl radical?

A) tetrahedral
B) trigonal planar
C) trigonal pyramidal
D) square planar

Question 37

What type of reactive intermediate is formed in the reaction of propene with N-bromosuccinimide to give 3-bromo-1-propene?

A) allylic carbocation
B) allylic carbanion
C) allylic radical
D) cyclic bromonium ion

Question 38

What is the characteristic of a radical chain termination step?

A) radicals are formed
B) substitution products are formed
C) a radical reacts with a molecule to give a new radical and a new molecule
D) two radicals combine to give a molecule

Question 39

What is the reactive intermediate in the autooxidation of cyclohexene?

A) an allylic radical
B) a 2 $\degree$ carbocation
C) a carbocation
D) a diene

Question 40

Which of the following statements is not true about the allyl radical

A) the carbon-carbon bond lengths are identical
B) the unpaired electron density is shared between carbons 1 and 2.
C) it undergoes reaction with bromine to give a single product
D) it is formed by abstraction of a hydrogen atom from the methyl group of propene

Question 41

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

Question 42

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

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

Question 43

Provide the IUPAC name of the following compound (shown as a Fischer projection).

Question 44

What is the structure of the key intermediate in the following reaction?

Question 45

What is the structure of all of the monobrominated products, including regioismers and stereoisomers, obtained from the following reaction?

Question 46

What are the major products formed upon treatment of (E) 3-methyl-2-hexene with HBr in the presence of peroxides?

A) only 1 and 2
B) only 1 and 4
C) only 2 and 3
D) a mixture of 1, 2, 3, and 4

Question 47

What are the major products formed upon treatment of (E) 3-methyl-2-hexene with HBr in the absence of peroxides?

A) only 1
B) only 2
C) a mixture of 1 and 2
D) only 3

Question 48

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

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

Question 49

Provide the IUPAC name of the following compound (shown as a Fischer projection).

Question 50

Provide the IUPAC name of the following compound.

Question 51

Provide neatly drawn resonance structures of the key intermediate in the following reaction.

Question 52

Provide the IUPAC name of the following compound.

Question 53

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

Question 54

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

Question 55

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

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

Question 56

What is the structure of all of the monobrominated products, including regioismers and stereoisomers, obtained from the following reaction?

Question 57

Which of the following accounts for the anti-Markovnikov regiochemistry of the reaction of an alkene with HBr in the presence of peroxides?

A) the alkene reacts with HBr to give a carbocation
B) the alkene reacts with a bromine atom to give a radical
C) the alkene reacts with a hydrogen atom to give a radical
D) the alkene reacts with peroxide to five an allylic radical

Question 58

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