Deck 7: Alkyl Halides and Nucleophilic Substitution

Question 1

Which of the following alkyl halides is a tertiary alkyl halide?

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

Answer 1

II

Question 2

Which of the following alkyl halides is a secondary alkyl halide?

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

Answer 2

III

Question 3

Rank the following halides in order of decreasing polarity,putting the most polar first.

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

Answer 3

IV > III > II > I

Question 4

Which of the following structures have the correct common name?

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

Question 5

Which of the following alkyl halides is a primary alkyl halide?

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

Question 6

What is the IUPAC name of the following compound?

A)2-Bromo-5,5-dimethylheptane
B)3,3-Dimethyl-6-bromoheptane
C)6-Bromo-3,3-dimethylheptane
D)2-Bromo-5,5-dimethyloctane

Question 7

What is the IUPAC name of the following compound?

A)trans-4-Methylcyclohexyl chloride
B)trans-p-Chloromethylcyclohexane
C)trans-4-Methyl-1-chlorocyclohexane
D)trans-1-Chloro-4-methylcyclohexane

Question 8

What is the IUPAC name of the following compound?

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

Question 9

Which of the following statements is true?

A)All good leaving groups are strong bases with weak conjugate acids.
B)Left-to-right across a row of the periodic table,leaving group ability decreases.
C)Down a column of the periodic table,leaving group ability decreases.
D)The conjugate bases of strong acids are good leaving groups.

Question 10

Which of the following structures have the correct common name?

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

Question 11

What is the IUPAC name of the following compound?

A)2-Methyl-4-chloropentane
B)2-Chloro-4-methylpentane
C)2-Chloro-1-isopropylpropane
D)2-Chloro-2-methylpentane

Question 12

Which of the following statements about the reactions of alkyl halides is true?

A)The characteristic reactions of alkyl halides are addition and elimination.
B)The characteristic reactions of alkyl halides are addition and substitution.
C)The characteristic reactions of alkyl halides are elimination and substitution.
D)The characteristic reactions of alkyl halides are oxidation and reduction.

Question 13

What is the IUPAC name of the following compound?

A)2-Chloro-4-isopropyl-2,6-dimethyloctane
B)2-Chloro-4-isopropyl-2,7-dimethylnonane
C)2,6-Dimethyl-2-chloro-4-isopropyloctane
D)7-Chloro-5-isopropyl-3,7-dimethyloctane

Question 14

What is the IUPAC name of the following compound?

A)2-Bromo-5-methyloctane
B)2-Bromo-3-methylheptane
C)2-Bromo-5-methylheptane
D)6-Bromo-3-methylheptane

Question 15

Rank the following in order of decreasing leaving group ability,putting the best first.

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

Question 16

Which of the following alkyl halides is a vinyl alkyl halide?

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

Question 17

Which of the following structures have the correct common name?

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

Question 18

What is the IUPAC name of the following compound?

A)(R)-3-Chloro-6-ethyloctane
B)(S)-3-Chloro-6-ethyloctane
C)(S)-6-Chloro-3-ethyloctane
D)(R)-6-Chloro-3-ethyloctane

Question 19

Rank the following molecules in order of increasing polarity,putting the least polar first.

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

Question 20

What is the IUPAC name of the following compound?

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

Question 21

The reaction of 1-bromobutane with sodium hydroxide affords the substitution product 1-butanol.What would happen to the rate of the reaction if the concentration of both 1-bromobutane and sodium hydroxide were doubled?

A)The rate remains the same.
B)The rate decreases by a factor of 2.
C)The rate increases by a factor of 2.
D)The rate increases by a factor of 4.

Question 22

The reaction of tert-butyl bromide,(CH₃)₃CBr,with ethanol affords the substitution product tert-butyl ethyl ether,(CH₃)₃COCH₂CH₃,in acidic conditions.What would happen to the rate of the reaction if the concentration of ethanol was doubled?

A)The rate remains the same.
B)The rate decreases by a factor of 2.
C)The rate increases by a factor of 2.
D)The rate increases by a factor of 4.

Question 23

Which of the following statements is not true?

A)In polar protic solvents,nucleophilicity decreases down a column of the periodic table as the size of the anion increases.
B)Nucleophilicity is affected by the solvent used in a substitution reaction.
C)Polar protic solvents are capable of intermolecular hydrogen bonding.
D)Polar protic solvents solvate both cations and anions.

Question 24

Which of the following solvents is not a polar protic solvent?

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

Question 25

Rank the alkyl halides in order of decreasing S_N2 reactivity,putting the most reactive first.

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

Question 26

Which of the following is a polar aprotic solvent?

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

Question 27

Which of the following statements is not true?

A)Sodium ethoxide is a better nucleophile than sodium tert-butoxide.
B)Sodium tert-butoxide and sodium ethoxide have similar strengths as bases.
C)Sterically hindered bases are also called nonnucleophilic bases.
D)Steric hindrance decreases basicity but not nucleophilicity.

Question 28

Which of the following is the most nucleophilic?

A)CH₄
B)H₂O
C)NH₃
D)HF

Question 29

Which of the following alkyl halides undergoes the fastest S_N2 reaction with sodium hydroxide?

A)1-Iodobutane
B)1-Chlorobutane
C)1-Fluorobutane
D)1-Bromobutane

Question 30

Rank the following in order of increasing nucleophilicity,putting the least nucleophilic first.

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

Question 31

Given the following substitution reaction,what would be the effect of changing the solvent from CH₃OH to (CH₃)₂S=O? CH₃(CH₂)₅Br + NaOH ® CH₃(CH₂)₅OH + Br^-

A)The rate would decrease because S_N1 reactions are favored by polar protic solvents.
B)The rate would increase because S_N2 reactions are favored by polar aprotic solvents.
C)The rate would increase because S_N1 reactions are favored by polar protic solvents.
D)The rate would decrease because S_N2 reactions are favored by polar aprotic solvents.

Question 32

Rank the following in order of decreasing nucleophilicity,putting the most nucleophilic first.

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

Question 33

Which compound is most likely to follow second-order kinetics in a substitution reaction?

A)CH₃Br
B)(CH₃)₃CCH₂Br
C)CH₃CH₂Br
D)(CH₃)₂CHBr

Question 34

Which of the following statements is not true?

A)All good leaving groups are weak bases with strong conjugate acids.
B)Left-to-right across a row of the periodic table,leaving group ability increases.
C)Down a column of the periodic table,leaving group ability increases.
D)Equilibrium favors the products of the nucleophilic substitution when the leaving group is a stronger base than the nucleophile.

Question 35

Which of the following anions is the most nucleophilic in polar aprotic solvents?

A)F^-
B)Cl^-
C)Br^-
D)I^-

Question 36

Which of the following statements about S_N2 reactions is true?

A)The rate of reaction is dependent on just the substrate.
B)The fastest reaction will occur with a tertiary alkyl halide.
C)The mechanism is a two-step process.
D)Displacement occurs with inversion of configuration.

Question 37

Which of the following statements about the S_N2 mechanism for nucleophilic substitution reactions is true?

A)Involves one step and occurs with retention of configuration.
B)Involves two steps and occurs with inversion of configuration.
C)Involves one step and occurs with inversion of configuration.
D)Involves one step and occurs with racemization.

Question 38

Rank the following ions in order of increasing nucleophilicity in polar protic solvents,starting with the least nucleophilic ion.

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

Question 39

The reaction of bromoethane with sodium acetate affords the substitution product methyl acetate.What is the effect of doubling the concentration of sodium acetate on the rate of the reaction?

A)The rate remains the same.
B)The rate decreases by a factor of 2.
C)The rate increases by a factor of 2.
D)The rate increases by a factor of 4.

Question 40

Rank the following in order of increasing leaving group ability,putting the worst leaving group first.

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

Question 41

Which of the following statements about the Hammond postulate is true?

A)In an exothermic reaction,lowering the energy of the transition state increases the activation energy,E_a.
B)In an endothermic reaction,the more stable product forms faster.
C)In an endothermic reaction,the less stable product forms faster.
D)In an endothermic reaction,the activation energy,E_a,is similar for both products.

Question 42

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 43

Which of the following alkyl halides will react fastest with CH₃OH in an S_N1 mechanism?

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

Question 44

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 45

Which of the following statements about an S_N1 reaction mechanism is true?

A)The reaction is fastest with primary alkyl halide.
B)The reaction exhibits a one-step mechanism.
C)The reaction rate increases as the leaving group ability increases.
D)The reaction rate increases as the strength of the nucleophile increases.

Question 46

Which of the following carbocations is the most stable?

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

Question 47

For the following reaction,use the identity of the alkyl halide and nucleophile to determine which substitution mechanism occurs.Then determine which solvent affords the faster reaction.

A)S_N1,CH₃OH
B)S_N1,HMPA
C)S_N2,CH₃OH
D)S_N2,HMPA

Question 48

Which of the following is not a characteristic of an S_N1 reaction?

A)The rate is proportional to the concentration of substrate.
B)The reaction is favored in polar protic solvents.
C)The rate is independent of the concentration of the nucleophile.
D)The electrophilic carbon undergoes inversion of stereochemistry.

Question 49

What is the rate-determining step of an S_N1 reaction mechanism?

A)Reaction of the nucleophile with the carbocation to form the product.
B)Breaking the bond between the carbon and the leaving group to generate a carbocation.
C)Attack of the nucleophile on the substrate to generate a pentavalent carbon.
D)None of these.

Question 50

Which of the following rate laws describes the kinetics of an S_N1 reaction?

A)Rate = k[alkyl halide]
B)Rate = k[alkyl halide][nucleophile]
C)Rate = k[nucleophile]
D)Rate = k[solvent]

Question 51

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 52

Which of the following statements about the Hammond postulate is not true?

A)The Hammond postulate provides a quantitative estimate of the energy of a transition state.
B)In endothermic reactions,the transition state is closer in energy to the products.
C)In exothermic reactions,the transition state is closer in energy to the reactants.
D)The Hammond postulate provides a qualitative estimate of the energy of a transition state.

Question 53

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 54

Rank the following carbocations in order of decreasing stability,putting the most stable first.

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

Question 55

Which of the following statements about carbocation stability is true?

A)Carbocations are stabilized by electron-withdrawing inductive effects only.
B)Carbocations are stabilized by electron-withdrawing inductive effects and hyperconjugation.
C)Carbocations are stabilized by electron-donating inductive effects only.
D)Carbocations are stabilized by electro-donating inductive effects and hyperconjugation.

Question 56

The reaction of what nucleophile and substrate is represented by the following transition state?

A)Methanol with 2-bromopropane
B)Methoxide with 2-bromopropane
C)Methoxide with 1-bromopropane
D)Methanol with 1-bromopropane

Question 57

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 58

For the following reaction,use the identity of the alkyl halide and nucleophile to determine which substitution mechanism occurs.Then determine which solvent affords the faster reaction.

A)S_N1,H₂O
B)S_N1,DMF
C)S_N2,H₂O
D)S_N2,DMF

Question 59

Which of the following statements about an S_N1 reaction mechanism is true?

A)The reaction involves two steps and occurs fastest with primary alkyl halides.
B)The reaction involves one step and occurs fastest with primary alkyl halides.
C)The reaction involves one step and occurs fastest with tertiary alkyl halides.
D)The reaction involves two steps and occurs fastest with tertiary alkyl halides.

Question 60

For the following reaction,use the identity of the alkyl halide and nucleophile to determine which substitution mechanism occurs.Then determine which solvent affords the faster reaction.

A)S_N1,CH₃OH
B)S_N1,DMSO
C)S_N2,CH₃OH
D)S_N2,DMSO

Question 61

Which of the following alkyl halides would react the fastest with H₂O in S_N1 reaction? CH₃CH₂CH₂CH₂Br,(CH₃)₂CHCH₂Br,CH₃CH₂CH(CH₃)Br,(CH₃)₃CBr

A)CH₃CH₂CH₂CH₂Br
B)(CH₃)₂CHCH₂Br
C)CH₃CH₂CH(CH₃)Br
D)(CH₃)₃CBr

Question 62

Which alkyl halide will form the most stable carbocation?

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

Question 63

What is the product of the nucleophilic substitution reaction shown below?

A)Only I
B)Only II
C)I and II
D)None

Question 64

What is the IUPAC name of the following compound?

A)(1R,3R)-1-bromo-3-isopropylcyclopentane
B)(1R,3S)-1-bromo-3-isopropylcyclopentane
C)(1S,3R)-1-bromo-3-isopropylcyclopentane
D)(1S,3S)-1-bromo-3-isopropylcyclopentane

Question 65

Identify the nucleophile and type of substitution reaction in the following:

A)CN^-,S_n1
B)CN^-,S_n2
C)Br^-,S_n1
D)Br^-,S_n2

Question 66

What is the starting material in the reaction shown below?

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

Question 67

What is the starting material in the reaction shown below?

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

Question 68

Rank the following compounds in order of increasing S_N1 reactivity?

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

Question 69

Which of the following alkyl halides would react the fastest with ^-OH in S_N2 reaction? CH₃CH₂Br,CH₃CH₂Cl,CH₃CH₂F,CH₃CH₂I

A)CH₃CH₂Br
B)CH₃CH₂Cl
C)CH₃CH₂F
D)CH₃CH₂I

Question 70

Rank the following compounds in order of increasing S_N2 reactivity?

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

Question 71

What is the IUPAC name of the following compound?

A)(3R,4R)-3-chloro-4-methylhexane
B)(3R,4S)-3-chloro-4-methylhexane
C)(3S,4R)-3-chloro-4-methylhexane
D)(3S,4S)-3-chloro-4-methylhexane

Question 72

Pick the solvent that gives the fastest S_N2 reaction between CH₂CH₂Br and ^-OCH₃.

A)CH₂CH₂OH
B)CH₃OH
C)DMSO
D)H₂O

Question 73

Which of the following statements explain why aryl halides and vinyl halides do not undergo nucleophilic substitution by either the S_N1 or S_N2 mechanism?

A)They don't undergo S_N1 reactions because a higher percent s-character makes the bond longer and stronger.
B)They don't undergo S_N2 reactions because a higher percent s-character makes the bond shorter and stronger.
C)They don't undergo S_N2 reactions because heterolysis of the C-X bond forms a highly unstable carbocation.
D)They don't undergo S_N1 reactions because the carbocation is highly electronegative.