Resction mechanism

Question 1

Which of the following favors an SN2 mechanism?

Answer 1

Primary alkyl halide in polar aprotic solvent

Question 2

What happens during the initiation step of free radical halogenation?

Answer 2

Cl₂ undergoes homolytic cleavage

Question 3

Which of the following is a propagation step in halogenation of methane?

Answer 3

Both b and c

Question 4

Termination in a radical chain reaction involves:

Answer 4

Radical recombination

Question 5

Which halogen is most selective in radical halogenation?

Answer 5

Br₂

Question 6

What is the mechanism for nitration of benzene?

Answer 6

Electrophilic aromatic substitution

Question 7

What is the electrophile in nitration of benzene?

Answer 7

NO₂⁺

Question 8

Friedel–Crafts alkylation uses:

Answer 8

RX and AlCl₃

Question 9

What type of reaction occurs when benzene is treated with Br₂ and FeBr₃?

Answer 9

Electrophilic aromatic substitution

Question 10

What is the function of AlCl₃ in Friedel–Crafts reactions?

Answer 10

Lewis acid catalyst

Question 11

Which compounds undergo nucleophilic acyl substitution?

Answer 11

Carboxylic acid derivatives

Question 12

What is the first step in acid-catalyzed ester hydrolysis?

Answer 12

Nucleophilic attack by water

Question 13

What are the products of amide hydrolysis under acidic conditions?

Answer 13

Ammonium ion and carboxylic acid

Question 14

What type of mechanism is Fischer esterification?

Answer 14

Nucleophilic acyl substitution

Question 15

Why are acid chlorides more reactive than esters?

Answer 15

Cl⁻ is a better leaving group

Question 16

What is the oxidation product of a primary alcohol with PCC?

Answer 16

Aldehyde

Question 17

Oxidation of a secondary alcohol with KMnO₄ gives:

Answer 17

Ketone

Question 18

Which reagent selectively reduces aldehydes and ketones?

Answer 18

NaBH₄

Question 19

Which of the following is a common oxidizing agent?

Answer 19

CrO₃

Question 20

What happens when a tertiary alcohol is oxidized?

Answer 20

No reaction

Question 21

Which reaction mechanism involves the formation of a carbocation intermediate?

Answer 21

SN1

Question 22

In an E2 elimination reaction, the base must abstract a proton from:

Answer 22

The β-carbon

Question 23

Which of the following solvents would favor an SN1 reaction?

Answer 23

Water

Question 24

Which of the following compounds undergoes a nucleophilic attack by a strong base in an E2 reaction?

Answer 24

2-Bromo-2-methylpropane

Question 25

Which of the following can undergo a Friedel–Crafts acylation?

Answer 25

Benzene

Question 26

Which of the following compounds undergoes nucleophilic substitution?

Answer 26

Methyl iodide

Question 27

What type of bond is broken in an SN2 mechanism?

Answer 27

A C-LG bond

Question 28

Which of the following is a hallmark of an E2 reaction?

Answer 28

A strong base abstracts a proton from the β-carbon

Question 29

Which of the following is true of a carbocation intermediate?

Answer 29

It is highly unstable and prone to rearrangements

Question 30

Which of the following will have the highest reactivity in an SN2 reaction?

Answer 30

Methyl chloride

Question 31

What is the product of the reaction between an alkene and Br₂ in CCl₄?

Answer 31

Vicinal dibromide

Question 32

What is the intermediate in a free radical halogenation of methane?

Answer 32

Methyl radical

Question 33

What is the main difference between SN1 and SN2 reactions?

Answer 33

SN1 involves a carbocation intermediate; SN2 does not.

Question 34

What is the major product of an alkene reaction with HBr in the presence of peroxide?

Answer 34

Anti-Markovnikov addition

Question 35

Which of the following compounds will undergo an electrophilic addition reaction?

Answer 35

Alkene

Question 36

Which of the following is true for the E1 mechanism?

Answer 36

The rate-determining step involves the departure of the leaving group

Question 37

What is the result of a hydration reaction of an alkene?

Answer 37

Alcohol

Question 38

Which of the following is the correct order of reactivity for electrophilic aromatic substitution?

Answer 38

Toluene > Benzene > Nitrobenzene

Question 39

What is the most stable intermediate in an SN1 reaction?

Answer 39

Tertiary carbocation

Question 40

Which of the following can result in the formation of a chiral center?

Answer 40

A reaction involving an alkene with a non-symmetrical substituent

Question 41

Which of the following is a characteristic of the E2 mechanism?

Answer 41

The reaction occurs in a single step with a strong base

Question 42

What is the key feature of the reaction between a halide and an alkene in an SN2 reaction?

Answer 42

Backside attack by the nucleophile

Question 43

What does the E1 mechanism often result in?

Answer 43

Zaitsev’s product (most substituted alkene)

Question 44

Which of the following reagents will not react with a primary alkyl halide in an SN2 mechanism?

Answer 44

Polar protic solvent

Question 45

What is the product when a terminal alkyne is treated with HCl?

Answer 45

Markovnikov addition of Cl

Question 46

Which of the following reactions produces a ketone?

Answer 46

Ozonolysis of an alkene

Question 47

Which of the following reactions produces a carboxylic acid?

Answer 47

Oxidation of a primary alcohol with KMnO₄

Question 48

What is the intermediate in the mechanism of nucleophilic substitution?

Answer 48

Tetrahedral transition state

Question 49

In an E2 reaction, how should the hydrogen and leaving group be positioned?

Answer 49

Anti-periplanar

Question 50

Which mechanism is favored by a strong, bulky base like t-BuOK?

Answer 50

E2