Question 1

Which of the following is the weakest nucleophile in protic solvent in an  SN2  reaction, and why?

Accepted Answer

Fluoride is the weakest nucleophile in protic solvent in an S_N2 reaction. Because it is the smallest of the nucleophiles shown, it is most easily solvated and must shed solvent molecules to react with an electrophile.

Question 2

Which of the following is a likely product of the reaction sequence shown?

Accepted Answer

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

Question 3

SN1  reactions run in polar solvents have faster rates than  SN1 reactions run in nonpolar solvents.
Which statement provides the best explanation for the difference in rates?

Accepted Answer

A)  Polar solvents stabilize the transition state in the rate-determining step. 
B)  Nonpolar solvents stabilize the transition state in the rate-determining step. 
C)  Polar solvents stabilize the carbocation intermediate. 
D)  Nonpolar solvents stabilize the carbocation intermediate. 
E)  The reaction mechanism is different in polar solvents than in nonpolar solvents. 
A)  Polar solvents stabilize the transition state in the rate-determining step. 
B)  Nonpolar solvents stabilize the transition state in the rate-determining step. 
C)  Polar solvents stabilize the carbocation intermediate. 
D)  Nonpolar solvents stabilize the carbocation intermediate. 
E)  The reaction mechanism is different in polar solvents than in nonpolar solvents. A

Question 4

Supply the reagents/intermediates in the multistep synthesis shown below.

Accepted Answer

The answer of Supply the reagents/intermediates in the multistep synthesis...

Question 5

Predict the product of the following reaction.

Accepted Answer

The answer of Predict the product of the following reaction....

Question 6

Which of the following is the rate limiting step in an  SN1 reaction?

Accepted Answer

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

Question 7

Draw an energy diagram for the  SN1  reaction between tert-butyl bromide and water; assume that the reaction is overall exothermic.

Accepted Answer

Question 8

For the following reaction, what will be the effect on the rate if  [NaN3]  is tripled?

Accepted Answer

A)  The rate doubles. 
B)  The rate triples. 
C)  The rate quadruples. 
D)  The rate stays the same. 
E)  There is not enough information to determine the effect. 
A)  The rate doubles. 
B)  The rate triples. 
C)  The rate quadruples. 
D)  The rate stays the same. 
E)  There is not enough information to determine the effect.

Question 9

Draw the structure of the alkyl bromide starting material necessary to react with a cyanide ion to
produce the molecule shown.

Accepted Answer

The answer of Draw the structure of the alkyl bromide...

Question 10

Which of these choices is the best leaving group?

Accepted Answer

A)   OH- 
B)   NH3 
C)   Cl- 
D)   CH3O- 
E)   H2O 
A)   OH- 
B)   NH3 
C)   Cl- 
D)   CH3O- 
E)   H2O

Question 11

Hydroxide is a poor leaving group. Describe three ways to convert the hydroxyl group to a better leaving group.

Accepted Answer

1. Convert the OH  group to a  Br  using

Question 12

Which of the following would react most rapidly in an  SN1 reaction?

Accepted Answer

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

Question 13

Which of the following is a Lewis acid but not a Brønsted acid?

Accepted Answer

A)  NH3 
B)   H2O 
C)   AlCl3 
D)   CH3OH 
E)   CH3CH2SH 
A)  NH3 
B)   H2O 
C)   AlCl3 
D)   CH3OH 
E)   CH3CH2SH

Question 14

Which of these carbocations is more stable? Explain.

Accepted Answer

Both are tertiary carbocations

Question 15

Which of the following would not be a valid reason for a substitution reaction being irreversible?

Accepted Answer

A) The reaction is highly exothermic. 
B) The reaction requires a catalyst to proceed. 
C) One product is a gas that bubbles out of the reaction medium. 
D) One product crystallizes out of the reaction medium. 
E) One reactant is present in a very large quantity relative to the other. 
A) The reaction is highly exothermic. 
B) The reaction requires a catalyst to proceed. 
C) One product is a gas that bubbles out of the reaction medium. 
D) One product crystallizes out of the reaction medium. 
E) One reactant is present in a very large quantity relative to the other.

Question 16

Based on nucleophile, substrate, and reaction conditions, state the most likely reaction mechanism  (SN1 or SN2)  in each example. Draw the products, including stereochemistry as needed.

Accepted Answer

Question 17

Outline a multistep synthesis of the target molecule from the starting material shown.You may
use any organic or inorganic reagents.Show the reagents necessary for each step and the product
of each step.

Accepted Answer

The answer of Outline a multistep synthesis of the target...

Question 18

Draw an energy diagram for the  SN2  reaction shown here. Show the correct relative energies of the starting materials and products.

Accepted Answer

Question 19

Explain why  SN2  reactions proceed with inversion of configuration at a stereogenic carbon, but product mixtures in  SN1  reactions show both inversion and retention of configuration.

Accepted Answer

S_N2 reactions are characterized by the i

Question 20

Which structure is the most likely  SN1 product under the following conditions?

Accepted Answer

A)   
B)   
C)   
D)   
E)  None of these products will form. 
A)   
B)   
C)   
D)   
E)  None of these products will form.

Exam 7: Substitution Reactions: the Sn2 and Sn1 Reactions

Which of the following is the weakest nucleophile in protic solvent in an SN2 reaction, and why?

Which of the following is a likely product of the reaction sequence shown?

SN1 reactions run in polar solvents have faster rates than SN1 reactions run in nonpolar solvents. Which statement provides the best explanation for the difference in rates?

Supply the reagents/intermediates in the multistep synthesis shown below.

Predict the product of the following reaction.

Which of the following is the rate limiting step in an SN1 reaction?

Draw an energy diagram for the SN1 reaction between tert-butyl bromide and water; assume that the reaction is overall exothermic.

For the following reaction, what will be the effect on the rate if [NaN3] is tripled?

Draw the structure of the alkyl bromide starting material necessary to react with a cyanide ion to produce the molecule shown.

Which of these choices is the best leaving group?

Hydroxide is a poor leaving group. Describe three ways to convert the hydroxyl group to a better leaving group.

Which of the following would react most rapidly in an SN1 reaction?

Which of the following is a Lewis acid but not a Brønsted acid?

Which of these carbocations is more stable? Explain.

Which of the following would not be a valid reason for a substitution reaction being irreversible?

Based on nucleophile, substrate, and reaction conditions, state the most likely reaction mechanism (SN1 or SN2) in each example. Draw the products, including stereochemistry as needed.

Outline a multistep synthesis of the target molecule from the starting material shown.You may use any organic or inorganic reagents.Show the reagents necessary for each step and the product of each step.

Draw an energy diagram for the SN2 reaction shown here. Show the correct relative energies of the starting materials and products.

Explain why SN2 reactions proceed with inversion of configuration at a stereogenic carbon, but product mixtures in SN1 reactions show both inversion and retention of configuration.

Which structure is the most likely SN1 product under the following conditions?

Atoms and Molecules; Orbitals and Bonding

Alkanes

Alkenes and Alkynes

Stereochemistry

Rings

Substituted Alkanes: Alkyl Halides, Alcohols, Amines, Ethers,thiols, and Thioethers

Elimination Reactions: the E1 and E2 Reactions

Analytical Chemistry: Spectroscopy

Electrophilic Additions to Alkenes

More Additions to Bonds

Radical Reactions

Dienes and the Allyl System: 2p Orbitals in Conjugation

Aromaticity

Substitution Reactions of Aromatic Compounds

Carbonyl Chemistry 1: Addition Reactions

Carboxylic Acids

Derivatives of Carboxylic Acids: Acyl Compounds

Carbonyl Chemistry 2: Reactions at the Α Position

Special Topic: Carbohydrates

Special Topic: Bio-Organic Chemistry

Special Topic: Amino Acids and Polyamino Acids Peptides and Proteins

Special Topic: Reactions Controlled by Orbital Symmetry

Special Topic: Intramolecular Reactions and Neighboring Group Participation

Filters

Which of the following is the weakest nucleophile in protic solvent in an S_N2 reaction, and why?

S_N1 reactions run in polar solvents have faster rates than S_N1 reactions run in nonpolar solvents. Which statement provides the best explanation for the difference in rates?

Which of the following is the rate limiting step in an S_N1 reaction?

Draw an energy diagram for the S_N1 reaction between tert-butyl bromide and water; assume that the reaction is overall exothermic.

For the following reaction, what will be the effect on the rate if [NaN₃] is tripled?

Which of the following would react most rapidly in an S_N1 reaction?

Based on nucleophile, substrate, and reaction conditions, state the most likely reaction mechanism (S_N1 or S_N2) in each example. Draw the products, including stereochemistry as needed.

Draw an energy diagram for the S_N2 reaction shown here. Show the correct relative energies of the starting materials and products.

Explain why S_N2 reactions proceed with inversion of configuration at a stereogenic carbon, but product mixtures in S_N1 reactions show both inversion and retention of configuration.

Which structure is the most likely S_N1 product under the following conditions?