Deck 10: An Introduction to Multistep Mechanisms: Sn1 and E1 Reactions

Question 1

What is the rate law for the following S_N2 reaction?

A)Rate = k[A]
B)Rate = k[B]
C)Rate = k[A]²
D)Rate = k[B]²
E)Rate = k[A][B]

Answer 1

Rate = k[A][B]

Question 2

Which of the following is true regarding S_N1 reactions?

A)The stereochemistry of S_N1 products has an R configuration exclusively.
B)The stereochemistry of S_N1 products has an S configuration exclusively.
C)S_N1 reactions produce racemic products in achiral environments.
D)S_N1 reactions are stereospecific.
E)S_N1 reactions produce cis isomers exclusively.

Answer 2

S_N1 reactions produce racemic products in achiral environments.

Question 3

What is the product of the following E2 reaction?

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

Answer 3

IV

Question 4

Which of the following steps could be found in an E1 mechanism?

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

Question 5

Which of the following could be the rate law for an S_N1 reaction?

A)Rate = k[A]
B)Rate = k[A]²
C)Rate = k[A][B]
D)Rate = k[A][B]²
E)Rate = k[A]²[B]²

Question 6

Which of the following steps could be found in an E1 mechanism?

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

Question 7

What is the most likely product of the following S_N2 reaction?

A)I
B)II
C)III
D)IV
E)A racemic mixture of II and III

Question 8

The following compound can undergo two successive S_N2 reactions.What are the products of these reactions?

A)I
B)II
C)III
D)IV
E)None of these pairs

Question 9

Which is not true of a free energy diagram for an S_N1 reaction?

A)It includes local energy minima between transition states.
B)It includes intermediates that are higher in energy than reactants or products.
C)It includes two transition states.
D)The heteolysis step always has the highest energy barrier.
E)All of the above are true.

Question 10

What is the most likely product of the following S_N1 reaction?

A)I
B)II
C)III
D)IV
E)A mixture of III and IV

Question 11

Which is true of a free energy diagram for an E1 reaction?

A)It proceeds through a carbocation intermediate.
B)It begins with the rate-determining step.
C)It includes two transition states.
D)It ends with alkene-containing products.
E)All of the above are true.

Question 12

Which is true of a free energy diagram for an S_N1 reaction?

A)It shows one transition state.
B)It always shows that the reaction is net exothermic.
C)It never shows intermediates.
D)It always shows that the reaction is net endothermic.
E)It always includes multiple energy barriers.

Question 13

For the rate law given below,what would happen to the rate of a reaction if the concentrations of [A] and [B] were doubled?
Rate = k[A][B]

A)The rate would stay the same.
B)The rate would double.
C)The rate would triple.
D)The rate would quadruple.
E)Not enough information is given to know.

Question 14

Which of the following steps could be found in an S_N1 mechanism?

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

Question 15

What is the product of the following E2 reaction?

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

Question 16

Which is the rate law for the following E1 reaction?

A)Rate = k[A]
B)Rate = k[B]
C)Rate = k[A]²
D)Rate = k[B]²
E)Rate = k[A][B]

Question 17

Which of the following steps could be found in an S_N1 mechanism?

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

Question 18

For the rate law given below,what would happen to the rate of a reaction if the concentration of [A] was doubled?
Rate = k[A][B]

A)The rate would slow by a factor of ½.
B)The rate would stay the same.
C)The rate would double.
D)The rate would triple.
E)The rate would quadruple.

Question 19

The following rate law could be possible for which of the following mechanisms?

A)E1
B)E2
C)S_N1
D)S_N2
E)E2 and S_N2

Question 20

Which of the following is true of S_N1 reactions?

A)They are stereospecific.
B)They occur in a single step.
C)They are second order.
D)They proceed through a carbocation intermediate.
E)Their rate is dependent on the concentration of attacking nucleophile.

Question 21

Draw the product(s)of the following intramolecular S_N1 reaction.

Question 22

The following alkyl bromide can react with NaF via an S_N1 mechanism.Draw the mechanism and product(s)of this reaction.Be sure to pay attention to stereochemistry,if applicable.

Question 23

Which of the following will not undergo a 1,2-hydride shift?

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

Question 24

Which of the following proton transfers is most likely to occur in an acidic solution?

A)I
B)II
C)III
D)IV
E)All of these are likely in an acidic solution.

Question 25

Draw a detailed free energy diagram for the following S_N1 reaction.Include and label the overall reactants,the overall products,the intermediate(s),the axis,and the transition state(s).

Question 26

Which of the following mechanism steps is not allowed?

A)I
B)II
C)III
D)IV
E)All are allowed.

Question 27

Which of the following would proceed though a carbocation rearrangement during an E1 reaction?

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

Question 28

Draw a detailed free energy diagram for the following S_N1 reaction.Include and label the overall reactants,the overall products,the intermediate(s),the axis,and the transition state(s).

Question 29

Draw a detailed free energy diagram for the following E1 reaction.Include and label the overall reactants,the overall products,the intermediate(s),the axis,and the transition state(s).

Question 30

What is the product of the following E1 reaction?

A)I
B)II
C)III
D)A mixture of II and III
E)An E1 reaction mechanism is not possible.

Question 31

The following alkyl halide can react with NaBr via an S_N1 mechanism.Draw the product(s)of this reaction.Be sure to pay attention to stereochemistry,if applicable.

Question 32

Draw the product(s)of the following E2 reaction.

Question 33

Which of the following would not proceed though a carbocation rearrangement during an S_N1 reaction?

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

Question 34

If the following compound undergoes a 1,2-hydride shift,what is the most likely product?

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

Question 35

For the following E2 reaction,what would happen to the rate if the concentration of A was doubled?

Question 36

Which of the following is true of intramolecular proton transfers?

A)They can occur only in basic conditions.
B)They can occur only in acidic conditions.
C)They can occur in both acidic and basic conditions.
D)They are the most common way in which protons are transferred.
E)They are not likely to occur.

Question 37

Which of the following would undergo a 1,2-methyl shift?

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

Question 38

Give the rate law and order for the following E1 reaction.

Question 39

With regard to rate laws,provide the order for E1,E2,S_N1,and S_N2 reactions.

Question 40

Draw the mechanism and the product(s)for the following E1 reaction.

Question 41

For the following S_N2 reaction,what would happen to the rate if the concentrations of both A and B were tripled?

Question 42

Draw the product(s)of the following E1 reaction.

Question 43

The following mechanism step is not reasonable.Explain why.

Question 44

When a leaving group and a hydrogen atom are 180° apart,they are considered to be _______.

Question 45

The following mechanism has an unreasonable step.Indicate which step is unreasonable,and explain why.

Question 46

Draw the product(s)of the following S_N1 reaction.

Question 47

Which of the following reactions produces a new stereocenter with unequal amounts of R and S configurations? Explain.

Question 48

S_N2 reactions require ________ attack of the substrate by the nucleophile.

Question 49

Explain why the following carbocation rearrangement is not likely.

Question 50

Draw the product(s)of the following E2 reaction.

Question 51

Are mechanism steps requiring three species likely? Explain why or why not.

Question 52

The following mechanism has an unreasonable step.Indicate which step is unreasonable,and explain why.

Question 53

A new tetrahedral stereocenter is produced in a step in which the reactants and the environment are achiral.How much of the R configuration can be expected?

Question 54

A reaction that produces a new stereocenter with only a single configuration is called _______.

Question 55

Explain why the following carbocation rearrangement is not likely.

Question 56

For the following S_N1 reaction,what would happen to the rate if the concentration of B was quadrupled?

Question 57

Draw the product(s)of the following S_N1 reaction.

Question 58

Draw the product(s)of the following E1 reaction.

Question 59

Draw the product(s)of the following E2 reaction.