Deck 22: Carboxylic Acids and Derivatives

Question 1

Which of the following peaks would you see in the IR spectrum of a carboxylic acid?

A) A flat line (carboxylic acids are not IR active)
B) A sharp line at 2250 cm^-1
C) A broad peak from 3800-2800 cm^-1
D) A broad peak from 800-600 cm^-1

Answer 1

A broad peak from 3800-2800 cm^-1

Question 2

Where is the carbonyl absorption found in the IR spectrum of a simple ester?

A) 2.5 ppm
B) 2250 cm^-1
C) 3800 cm^-1
D) 1740 cm^-1

Answer 2

1740 cm^-1

Question 3

What is the IUPAC name for the following compound?

A) methyl 3-methylbutanamide
B) 5-methylhexanamide
C) N-methyl 3-methylhexanamide
D) N-methyl 3-methylbutanamide

Answer 3

N-methyl 3-methylbutanamide

Question 4

Why is an amide less reactive to nucleophilic acyl substitution than an acid chloride?

A) Nitrogen is a better leaving group.
B) Chloride is a better leaving group.
C) Nitrogen donates more electron density into the carbonyl.
D) The amide anion is less basic.

Question 5

What is the IUPAC name for the following compound?

A) 4-fluoro-3-methylbenzoate
B) 4-fluoro-3-methylbenzoic acid
C) 3-methyl-4-fluorobenzoic acid
D) 4-fluoro-5-methylbenzoic acid

Question 6

Will the following reaction occur?

A) Yes
B) No

Question 7

Why doesn't nucleophilic acyl substitution stop at the tetrahedral intermediate?

A) The nucleophile is too basic.
B) Reforming the carbonyl is energetically favorable.
C) The leaving group is unstable and wants to be negatively charged.
D) There is no tetrahedral intermediate.

Question 8

Where do the carbonyl signals appear in the ¹³C NMR spectrum of carboxylic acid derivatives?

A) 1700 cm^-1
B) 180-160 ppm
C) 2.5-3.0 ppm
D) 100-80 ppm

Question 9

Why is pyridine included in the reaction of an acid chloride and an amine or alcohol?

A) Pyridine will deprotonate the amine or alcohol, making it a better nucleophile.
B) Pyridine will neutralize the acid by-product of the reaction.
C) Pyridine will protonate the carbonyl of the acid chloride, making it more reactive.
D) Pyridine will absorb the heat of the reaction.

Question 10

You see an absorption at 2250 cm^-1 in the IR spectrum of a compound. What kind of functional group is present?

A) A ketone
B) An aldehyde
C) An ester
D) A nitrile

Question 11

What is the first step in the general mechanism for nucleophilic acyl substitution?

A) Protonation of the carbonyl
B) Removal of an $\alpha$ -proton
C) Addition of the nucleophile to the carbonyl
D) Loss of the leaving group

Question 12

What is the structure for ethyl 4-chlorobenzoate?

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

Question 13

What is the IUPAC name for the following compound?

A) 2-fluorobutanonitrile
B) 2-fluoropentanonitrile
C) 3-fluoropentanonitrile
D) 2-fluorobutylcyanide

Question 14

What is the structure for 3-cyanocyclopentanone?

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

Question 15

Will the following reaction occur?

A) Yes
B) No

Question 16

Which structure is consistent with the following ¹H NMR spectrum?

A) ethyl acetate
B) 2-propanone
C) 3,3-dimethyl-2-pentanone
D) ethyl 2,2-dimethylpropionate

Question 17

What is the structure for acetic propanoic anhydride?

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

Question 18

What is the product of the following reaction?

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

Question 19

Which of the following is a lactam?

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

Question 20

Will the following reaction occur?

A) Yes
B) No

Question 21

What is the product of the following reaction (after acidic work-up)?

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

Question 22

What is the product of the following reaction?

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

Question 23

How can you convert a carboxylic acid into an ester?

A) Heat with an alcohol and catalytic acid
B) Deprotonate with a base and react with an alcohol
C) Deprotonate with a base and react with an alkyl halide
D) Both (a) heat with an alcohol and catalytic acid and (c) deprotonate with a base and react with an alkyl halide
E) Both (a) heat with an alcohol and catalytic acid and (b) deprotonate with a base and react with an alcohol

Question 24

What is the product of the following reaction?

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

Question 25

Rank the following compounds in order of increasing reactivity in nucleophilic acyl substitution.

A) I > II > III
B) III > II > I
C) II > III > I
D) III > I > II

Question 26

What is the direct product of the base-promoted hydrolysis of an ester?

A) A nitrile
B) A carboxylic acid
C) An amide
D) A carboxylic acid salt

Question 27

Which of the following two amides will react more readily with a nucleophile? Why?

A) I, because it is less hindered
B) II, because it is less hindered
C) I, because it is more strained
D) II, because it is more strained

Question 28

What is the product of the following reaction?

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

Question 29

What is the product of the following reaction?

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

Question 30

What is the product of the following reaction?

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

Question 31

What is the structure for the compound whose IUPAC name is pentyl 2-methylbutanoate?

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

Question 32

What reagent would you use for the following transformation?

A) LiAlH₄
B) DIBAL-H
C) NaBH₄
D) H₂, Pd/C

Question 33

How can you convert a carboxylic acid into an acid chloride?

A) Heat with hydrochloric acid
B) React with thionyl chloride (SOCl₂)
C) React with sodium chloride
D) React with Cl₂ and FeCl₃

Question 34

What is the product of the following reaction?

A) Hexanoic acid
B) 1-Hexanamide
C) Hexanal
D) 1-Hexanamine

Question 35

What is the product of the following reaction?

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

Question 36

What is the product of the following reaction?

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

Question 37

Which of the following reaction conditions can be used to synthesize an ester (RCOOR')?

A) RCOCl + R'NH₂ + pyridine
B) RCOOH + R'OH + H⁺
C) RCOOH + R'OH + OH^-
D) RCONH₂ + R'OH

Question 38

What is the missing reagent in the reaction below?

A) acetic acid
B) NaOMe
C) SOCl₂
D) pyridine

Question 39

What is the product of the following reaction?

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

Question 40

What is the IUPAC name for the following compound?

A) Propionyl phenol
B) Phenyl propanoate
C) Phenol propanoate
D) Phenyl acetate

Question 41

Which of the following statements about amides is true?

A) Amides react with methyl alcohol in the presence of an acid catalyst to form an ester.
B) Amides are hydrolyzed in acid or base to form carboxylic acids or carboxylate anions.
C) Amides react with thionyl chloride to form the acid chloride.
D) Amides do not react under any conditions. They are inert compounds.

Question 42

Which of the following substrates cannot be used as an immediate precursor to synthesize an ester?

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

Question 43

Draw the structure of N-phenyl acetamide.

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

Question 44

All of the following contain sp² hybridized atoms in their functional group except

A) a carboxylic acid
B) a nitrile
C) an aldehyde
D) an anhydride

Question 45

n-Butanenitrile will undergo all of the following listed reactions except one. Which reaction listed is not true for n-butanenitrile?

A) n-Butane nitrile will react with ethylmagnesium bromide to form an alcohol.
B) n-Butanenitrile with be reduced to butyl amine in the presence of LiAlH₄ with an aqueous work-up.
C) n-Butanenitrile is hydrolyzed in the presence of acid to form butanoic acid.
D) n-Butanenitrile is reduced with DIBAL-H to form n-butanal.

Question 46

An unknown compound has a sharp, medium peak at 2250 cm^-1. The unknown compound is probably

A) an alkane
B) an aldehyde
C) an alkene
D) a nitrile

Question 47

From the list below, pick the compound that does not react with acetyl chloride.

A) Isopropyl alcohol
B) Benzoic acid
C) Ammonia
D) Triethyl amine