Deck 11: Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations

Question 1

Exhibit 11-7
To answer the following question(s) consider the data below:
Reaction of bromomethane with sodium hydroxide in water forms methanol.If sodium iodide is added to the reaction mixture,the rate of methanol formation is dramatically increased (i.e.sodium iodide is a catalyst).
Refer to Exhibit 11-7.Write a reaction pathway that accounts for the effect of added NaI.

Answer 1

Question 2

Exhibit 11-6
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-6.Compound C is the:

A)S_N2 product
B)S_N1 product
C)E2 product
D)E1 product

Answer 2

E1 product

Question 3

Exhibit 11-4
Consider the pair of reactions below to answer the following question(s).
Refer to Exhibit 11-4.The alkyl bromide starting materials in these reactions are classified as:

A)3°
B)2°
C)1°
D)4°

Answer 3

1°

Question 4

Exhibit 11-7
To answer the following question(s) consider the data below:
Reaction of bromomethane with sodium hydroxide in water forms methanol.If sodium iodide is added to the reaction mixture,the rate of methanol formation is dramatically increased (i.e.sodium iodide is a catalyst).
Refer to Exhibit 11-7.The mechanism involved in the reaction of CH₃Br and NaOH is:

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

Question 5

Exhibit 11-9
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-9.Write the complete stepwise mechanism for this reaction.Clearly show the formation of both products.Show all electron flow with arrows and draw all intermediate structures.

Question 6

Exhibit 11-7
To answer the following question(s) consider the data below:
Reaction of bromomethane with sodium hydroxide in water forms methanol.If sodium iodide is added to the reaction mixture,the rate of methanol formation is dramatically increased (i.e.sodium iodide is a catalyst).
Would you expect the same catalytic effect on this reaction if you added NaCl instead? Explain your answer.

Question 7

Exhibit 11-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-11.List all chirality centers in the starting material by number.

Question 8

Exhibit 11-6
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-6.Compound B is the:

A)S_N2 product
B)S_N1 product
C)E2 product
D)E1 product

Question 9

Exhibit 11-4
Consider the pair of reactions below to answer the following question(s).
Refer to Exhibit 11-4.Which reaction is faster?

A) or
B)

Question 10

Exhibit 11-7
To answer the following question(s) consider the data below:
Reaction of bromomethane with sodium hydroxide in water forms methanol.If sodium iodide is added to the reaction mixture,the rate of methanol formation is dramatically increased (i.e.sodium iodide is a catalyst).
Refer to Exhibit 11-7.Draw a reaction energy diagram showing the two different reaction pathways (i.e.catalyzed and uncatalyzed).Indicate structures for all energy minima in the diagram.

Question 11

Exhibit 11-4
Consider the pair of reactions below to answer the following question(s).
Refer to Exhibit 11-4.The solvent in these reactions is:

A)nonpolar aprotic
B)polar aprotic
C)polar protic
D)nonpolar protic

Question 12

Exhibit 11-9
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-9.This reaction obeys a rate law of the form:

A)rate = k[RCl][CH₃CH₂OH]
B)rate = k[RCl][H₂O][CH₃CH₂OH]
C)rate = k[RCl]
D)rate = k[RCl][H₂O]

Question 13

Exhibit 11-6
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-6.Write the complete reaction mechanism for the formation of Compound C in this reaction.

Question 14

Exhibit 11-6
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-6.The substrate in the reaction is:

Question 15

Exhibit 11-4
Consider the pair of reactions below to answer the following question(s).
Refer to Exhibit 11-4.The nucleophile in these reactions is:

A)K⁺
B)alkyl group
C)Br−
D)I−

Question 16

Exhibit 11-7
To answer the following question(s) consider the data below:
Reaction of bromomethane with sodium hydroxide in water forms methanol.If sodium iodide is added to the reaction mixture,the rate of methanol formation is dramatically increased (i.e.sodium iodide is a catalyst).
Refer to Exhibit 11-7.Explain why adding NaI increases the reaction rate.

Question 17

Exhibit 11-8
Consider the reaction below to answer the following question(s):
Refer to Exhibit 11-8.Draw a Newman projection of the reactive conformation of the starting material.

Question 18

Exhibit 11-8
Consider the reaction below to answer the following question(s):
Refer to Exhibit 11-8.Write the product that results from the electron flow in the reaction,clearly indicating any stereochemistry.

Question 19

Exhibit 11-4
Consider the pair of reactions below to answer the following question(s).
Refer to Exhibit 11-4.The mechanism for these reactions is:

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

Question 20

Exhibit 11-8
Consider the reaction below to answer the following question(s):
Refer to Exhibit 11-8.The mechanism of this reaction is:

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

Question 21

For the elimination reaction: Draw the structure present at the point indicated by the asterisk (*) on the following energy diagram

Question 22

Draw the E2 mechanism of the reaction involving the reduction of 2-chloro-butane to 2-butene,in the presence of KOH in ethanol.​

Question 23

For the elimination reaction: Draw the structure present at the point indicated by the asterisk (*) on the following energy diagram.

Question 24

Consider the two lines shown on the energy diagram below. In an S_N2 reaction,

A)the upper left line could represent Cl^- and the lower left line I^-.
B)the upper left line could represent OH^- and the lower left line CH₃COO^- .
C)the upper left line could represent H₂O and the lower left line H₂S.
D)the upper left line could represent (CH₃)₂NH and the lower left line (CH₃)₂N^-.

Question 25

​Draw the mechanism of the S_N1 reaction of 2-chloro-2-methyl-butane with H₂O.

Question 26

Nucleophilic substitution and elimination reactions often compete with one another.In general,which of the following would enhance the rate of the E2 reaction over the S_N2 reaction?

A)use of a weak nucleophile
B)branching at the α or β carbon
C)use of a weak base
D)All of the above would enhance the E2 rate.

Question 27

Exhibit 11-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-11.As indicated by the carbon numbers,during the course of this reaction the bond between the nitrogen atom and carbon 3 is broken and a bond between the nitrogen atom and carbon 2 is formed.On the structures provided below,draw arrows showing electron flow for the mechanism that accounts for these bonding changes.

Question 28

Consider the two energy diagrams given below. A B Which of the following is correct with respect to these diagrams?

A)A could represent an E2 reaction.
B)B could represent an E1 reaction.
C)A could represent an E1cb reaction.

Question 29

​Draw the mechanism of the S_N2 reaction involving (R)-2-chloro-butane,to produce (S)-2-butanol.

Question 30

Consider the two energy diagrams below for an S_N2 reaction. A B Which of the following is correct?:

A)The change in the variable shown in A affects the transition state while that of B affects the reactant.
B)The change in the variable shown in A affects the reactant while that of B affects the transition state.
C)The changes in the variables shown in both A and B affect the transition state.
D)The changes in the variables shown in both A and B affect the reactants.

Question 31

Consider the two lines shown on the energy diagram below. In an S_N2 reaction,these lines could compare the effect of which of the following solvents?

A)CH₃OH and CH₃CH₂OH
B)CH₃OH and H₂O
C)CH₃OH and CH₃CN
D)DMSO and CH₃CN

Question 32

For the substitution reaction: Draw the structure present at the point indicated by the asterisk (*) on the following energy diagram.Identify the reactant as R or S or neither.

Question 33

Exhibit 11-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 11-11.If the absolute configuration at carbon 2 in the starting material is R,what is the absolute configuration at carbon 2 in the product?

Question 34

For the substitution reaction: Draw the structure present at the point indicated by the asterisk (*) on the following energy diagram.