Deck 8: Elimination Reactions: the E1 and E2 Reactions

Question 1

What will happen to the rate of the reaction below if the concentration of the alkyl chloride is doubled and the concentration of the sodium ethoxide is cut in half?

A)The rate will double.
B)The rate will decrease by a factor of two.
C)The rate will quadruple.
D)The rate will decrease by a factor of four.
E)The rate will remain the same.

Answer 1

The rate will remain the same.

Question 2

Which of the following carbocations is (are) most likely to rearrange?

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

Answer 2

II, III, and IV

Question 3

What will happen to the rate of the reaction below if the concentration of the bromide is tripled?

A) The rate will double.
B) The rate will be cut in half.
C) The rate will decrease by a factor of one-third.
D) The rate will increase by a factor of nine.
E) The rate will triple.

Answer 3

The rate will triple.

Question 4

Which is the most likely product of the reaction shown here?

A)
B)
C)
D)
E)

Question 5

What is the major S_N1 product of the following reaction?

A)
B)
C)
D)
E)

Question 6

Ehats the major E1 product of this reaction ?

A)
B)
C)
D)
E)

Question 7

Which of these is the most stable carbanion?

A)A
B)B
C)C
D)D
E)E

Question 8

What will happen to the rate of the reaction below if the concentration of ethanol is doubled?

A) The rate will double.
B) The rate will be cut in half.
C) The rate will be unaffected.
D) The rate will increase by a factor of four.
E) The rate will decrease by a factor of four.

Question 9

What is the major E1 product of the reaction ?

A)
B)
C)
D)
E)

Question 10

Which of the following statements is true?

A)The formation of the kinetic product has a higher activation energy than the formation of the thermodynamic product.
B)The kinetic product is more stable than the thermodynamic product.
C)The thermodynamic product forms faster than the kinetic product.
D)The transition state leading to the kinetic product is lower in energy than those leading to alternative products.
E)The kinetic and thermodynamic products form at the same rate; it is the energy difference between them that determines product distribution.

Question 11

Which of the following intermediates has the lowest activation energy for its formation, assuming identical leaving groups?

A) A
B) B
C) C
D) D
E) E

Question 12

Which of the following carbocations is least likely to rearrange?

A)A
B)B
C)C
D)D
E)E

Question 13

Which is the least likely product of the reaction shown here?

A)
B)
C)
D)
E) All four products are equally likely to form .

Question 14

What is the major product of this reaction?

A)
B)
C)
D)
E)

Question 15

In which of these reactions do you expect the structure of the transition state to most closely resemble the structure of the product?

A) I
B) II
C) III
D) II and III
E) I, II, and III

Question 16

What will happen to the rate of the reaction below if the concentration of potassium tert-butoxide is doubled?

A)The rate will double.
B)The rate will triple.
C)The rate will quadruple.
D)The rate will increase by a factor of 1.5.
E)The rate will remain the same.

Question 17

Which of these structures shows the preferred conformation for an E2 reaction to occur?

A)
B)
C)
D)
E)

Question 18

Consider the energy diagram for the multistep reaction shown here.Which statement about this diagram is not true?

A)C is the kinetic product.
B)D is the thermodynamic product.
C)Given sufficient energy, C and D can equilibrate.
D)Formation of D is under thermodynamic control.
E)Formation of C is under thermodynamic control.

Question 19

A)
B)
C)
D)
E)

Question 20

Which of the following statements is true about the two processes shown here?

A)A forms faster than B because A is more stable.
B)B forms faster than A because B is more stable.
C)A forms faster than B because the transition state leading to A is lower in energy than the transition state leading to B.
D)B forms faster than A because the transition state leading to B is lower in energy than the transition state leading to A.
E)A and B form at the same rate.

Question 21

Use the Hammond postulate to predict which of the following processes will be faster, and to
explain the difference in rates of formation of carbocation A and carbocation B.

Question 22

Draw the product of the following E2 reaction.

Question 23

State the Hammond postulate.

Question 24

In the presence of aqueous sulfuric acid, (E)-3-methyl-2-pentene can be protonated at two
different carbons to provide two different carbocation intermediates.Draw one energy diagram
showing both possible protonation events.Include in your diagram
a.the product of each of these protonation steps,
b.the relative energies of the transition states leading to these products, and
c.the relative energies of these products.

Question 25

Draw the major organic product of the following reaction.

Question 26

Draw a mechanism to rationalize the formation of the alkene product shown in the following
transformation.

Question 27

Draw a mechanism to rationalize the formation of the alkene product shown in the following
transformation.

Question 28

Explain why Reaction A would give more E2 product than Reaction B, while Reaction B would give more S_N2 product than Reaction A.
Reaction A:

Reaction B:

Question 29

Which of the following is the product of the reaction conditions shown?

A)
B)
C)
D)
E)

Question 30

Draw the product of the following E2 reaction and provide a mechanism for its formation.

Question 31

Draw the substitution product that would result from each reaction below.Indicate which reaction
would occur faster and provide an explanation for your answer using any necessary diagrams and
structures as support.

Question 32

Which of the following reactions would give relatively more E2 than SN2 product?
Reaction A:

Reaction B:

Question 33

Which of the following structures is not a possible product of the reaction shown here?

A)
B)
C)
D)
E)

Question 34

The reaction shown here is the pinacol rearrangement.It uses patterns of reactivity and
mechanism you have already seen.Provide a mechanism to rationalize the formation of the
product shown in this reaction.

Question 35

Draw the major El product of the following reaction.

Question 36

Suppose that in the E1 reaction shown here-the dehydration of cyclopentanol-a nonpolar
solvent like hexane was used instead of water.What would be the effect on the rate of reaction
compared to using water as solvent, and why?

Question 37

Draw the product of the following E2 reaction and provide a mechanism for its formation.

Question 38

Draw the structures of all possible El and S_N1 products that can form under the conditions shown.

Question 39

Draw the product of the following E2 reaction. Show stereochemistry at all stereogenic carbons.

Question 40

Explain the difference between kinetic control and thermodynamic control.

Question 41

Predict the product of the following reaction conditions and draw a mechanism to rationalize its
formation.Include all necessary lone pairs of electrons, curved arrows, and nonzero formal
charges.

Question 42

Draw a mechanism to account for the formation of the product shown here.

Question 43

Draw all the possible addition products formed in the reaction shown.

Question 44

Propose a mechanism to account for the formation of the observed product.

Question 45

Propose a mechanism to account for the formation of the observed product.