Deck 20: Carboxylic Acids

Question 1

Provide the name of the compound shown below.

Answer 1

2,5-dimethyl-4-hexenoic acid or 2,5-dimethylhex-4-enoic acid

Question 2

Provide the structure of 3,3-dimethylheptanoic acid.

Answer 2

CH₃CH₂CH₂CH₂C(CH₃)₂CH₂CO₂H

Question 3

What is the common name for the following compound?

A) γ-hydroxyvaleric acid
B) γ-hydroxypentanoic acid
C) γ-hydroxy-γ-methylbutyric acid
D) δ-hydroxyvaleric acid

Answer 3

γ-hydroxyvaleric acid

Question 4

Name the compound shown below.

Question 5

Carboxylic acids boil at considerably higher temperatures than do alcohols, ketones, or aldehydes of similar molecular weights. This is because they ________.

A) have a greater oxygen content
B) are more acidic
C) form stable hydrogen-bonded dimers
D) are hydrophobic
E) none of the above

Question 6

Provide the IUPAC name for the compound shown below.

Question 7

Provide the IUPAC name for the compound shown below.

Question 8

Provide the IUPAC name for the compound shown below.

Question 9

Name the compound shown below.

Question 10

Draw an acetic acid dimer. Be sure to indicate the hydrogen bonds present.

Question 11

Provide the IUPAC name for HO₂CCH₂C(CH₃)₂CH₂CH₂CO₂H.

Question 12

Provide the structure of glutaric acid.

Question 13

Provide the structure of pent-3-ynoic acid.

Question 14

Name the compound shown below.

Question 15

Provide the structure of 3-nitrophthalic acid.

Question 16

The common name for pentanedioic acid is ________.

A) pimelic acid
B) oxalic acid
C) glutaric acid
D) succinic acid
E) adipic acid

Question 17

Provide the structure of trans-1,3-cyclohexanedicarboxylic acid.

Question 18

Are carboxylic acids of more than 10 carbons more soluble in polar or nonpolar solvents?

Question 19

The combination of a carbonyl group and a hydroxyl group on the same carbon atom is called a ________ group.

A) carbamate
B) carbonate
C) urethane
D) carboxyl
E) carboxylate

Question 20

Provide the structure of succinic acid.

Question 21

What products result from the reaction of sodium propanoate with hydrobromic acid?

Question 22

Show the deprotonation of benzoic acid by hydroxide and draw the important resonance structures of the carboxylate ion.

Question 23

An ether solution of PhCO₂H (A), PhNH₂ (B), and PhCH₃ (C) is extracted with aqueous NaOH. The ether layer will contain what compound(s) after the extraction?

A) A + B
B) A + C
C) B + C
D) A + B + C
E) A only

Question 24

The pKa₁ for oxalic acid (pKa = 1.27) is much lower than the pKa₁ of glutaric acid (pKa = 4.35). Briefly explain why.

Question 25

What salt results from the reaction of benzoic acid with potassium hydroxide?

Question 26

An unknown compound is insoluble in water but dissolves in an aqueous solution of sodium bicarbonate with a release of carbon dioxide bubbles. The compound is almost certainly ________.

A) a carboxylic acid
B) an amine
C) an aldehyde
D) an alkyl chloride
E) an alcohol

Question 27

The strongest dichlorobutanoic acid is ________.

A) 2,2-dichlorobutanoic acid
B) 2,3-dichlorobutanoic acid
C) 3,3-dichlorobutanoic acid
D) 3,4-dichlorobutanoic acid
E) 4,4-dichlorobutanoic acid

Question 28

Which of the following sequences ranks the structures below in order of increasing
Acidity?

A) 1 < 2 < 3
B) 2 < 3 < 1
C) 3 < 1 < 2
D) 2 < 1 < 3

Question 29

Using acid-base extractions, how might you purify a crude sample of benzoic acid?

Question 30

Which of the following is the strongest acid?

A) chloroacetic acid
B) dichloroacetic acid
C) trichloroacetic acid
D) acetic acid

Question 31

In glutaric acid (HOOCCH₂CH₂CH₂COOH), pKa₁ is 4.35 while the pKa₂ is 5.42. Why is the second carboxylic acid less acidic?

Question 32

List the following weak acids in order of increasing acidity (from lowest to highest.).

A) 4 < 3 < 2 < 1 < 5
B) 4 < 1 < 3 < 2 < 5
C) 5 < 2 < 3 < 1 < 4
D) 4 < 1 < 2 < 5 < 3
E) 1 < 2 < 4 < 3 < 5

Question 33

Which of the following is the strongest acid?

A) acetic acid
B) chloroacetic acid
C) bromoacetic acid
D) fluoroacetic acid

Question 34

Which of the following is the strongest acid?

A) (CH₃)₂CHCO₂H
B) CH₃CH₂CO₂H
C) CH₃OCH₂CO₂H
D) PhCH₂CO₂H
E) O₂NCH₂CO₂H

Question 35

The 1H NMR spectrum of an unknown acid has the following peaks:
Δ (ppm) = 12.71 (1H, s), 8.04 (2H, d), 7.30 (2H, d), 2.41 (3H, s)
Which structure best fits this spectral information?

A)
B)
C)
D)

Question 36

Why are the OH groups of carboxylic acids more acidic than alcohols?

A) resonance stabilization of the carboxylate ion
B) inductive electron donating by the carbonyl oxygen
C) reduced hydrogen bonding capacity
D) because they have lower pKa values
E) None of the above - carboxylic acids are not more acidic than alcohols.

Question 37

Which of the following compounds is the strongest acid?

A) p-nitrobenzoic acid
B) p-bromobenzoic acid
C) m-methylbenzoic acid
D) m-methoxybenzoic acid
E) water

Question 38

Provide the major organic product of the reaction shown below.

Question 39

Name the salt formed from the reaction of acetic acid with ammonia.

Question 40

After completing the synthesis of 3-methylpentanoic acid, which of the following treatments will neutralize the mineral acids and facilitate the distribution of the organic acid from the organic layer to the aqueous extraction layer?

A) extraction with aqueous NaCl
B) extraction with ether
C) extraction with aqueous NaHCO₃
D) extraction with water
E) extraction with dilute aqueous HCl

Question 41

In the mass spectrum of 3-methylhexanoic acid, predict the mass of the fragment resulting from a McLafferty rearrangement.

Question 42

Carboxylic acids can be made from Grignards by treating the Grignard reagents with ________.

A) carbon monoxide
B) esters
C) aldehydes
D) diborane
E) carbon dioxide

Question 43

What two features are prominent in the infrared spectrum of a carboxylic acid?

Question 44

How does the O-H stretch in the IR spectrum of a carboxylic acid differ from the O-H stretch of an alcohol?

Question 45

In a carboxylic acid, the hybridization of the C is ________ and the OCO bond angle is ________.

A) sp²; exactly 120°
B) sp²; greater than 120°
C) sp³; 109.5°
D) sp³; less than 120°

Question 46

Provide the major organic product of the following reaction.

Question 47

Provide the major organic product of the following reaction.

Question 48

2-Phenylethanol yields what acid upon treatment with cold chromic acid?

Question 49

Where would one expect to find the ¹H NMR signal for the carboxyl group's hydrogen in propanoic acid?

A) δ 4.1 - 5.6 ppm
B) δ 10 - 13 ppm
C) δ 8 - 9 ppm
D) δ 6.1 - 7.8 ppm
E) δ 9.5 - 10 ppm

Question 50

An acid which could not be prepared by the reaction of an organic halide with cyanide ion followed by acid hydrolysis of the nitrile is ________.

A) propanoic acid
B) phenylacetic acid
C) acetic acid
D) (CH₃₎₃CCO₂H
E) CH₃(CH₂)₁₄CO₂H

Question 51

Which of the following must be converted into a carboxylic acid through nitrile hydrolysis rather than through a Grignard synthesis with Mg/ether followed with dry CO₂ and work-up with H₃O⁺?

Question 52

Deduce a reasonable structure for the compound which exhibits the following spectroscopic data.
C₅H₉ClO₂: IR: 2700-3400 cm^-1 (broad), 1710 cm^-1; ¹H NMR (ppm): 1.40 (6H, singlet), 3.60 (2H, singlet), 10.1 (1H, singlet) ppm.

Question 53

In the mass spectrum of pentanoic acid, the base peak occurs at m/z ________.

A) 102
B) 101
C) 85
D) 73
E) 60

Question 54

Starting with any alkene, how could you make pimelic acid (HOOC(CH₂)₅COOH)?

Question 55

What compound is produced when cyclohexene is treated with concentrated KMnO₄?

A) hexanoic acid
B) adipic acid
C) cyclohexanecarboxylic acid
D) benzoic acid
E) succinic acid

Question 56

1-Hexanol reacts with chromic acid to yield what product?

Question 57

What compound is produced when (CH₃)₂CHCH₂Br is subjected to the following sequence of steps?
1) Mg, Et₂O 2. CO₂

A) 2-methylpropanoic acid
B) 3-methylpropanoic acid
C) 2-methylbutanoic acid
D) 3-methylbutanoic acid
E) 2-methylhexanoic acid

Question 58

An acid which could not be prepared from an organic halide by carboxylation of the Grignard reagent is ________.

A) benzoic acid
B) 2,2-dimethylpropanoic acid
C) propanoic acid
D) 4-oxocyclohexanecarboxylic acid
E) 2-methylbutanoic acid

Question 59

Provide the major organic product of the following reaction.

Question 60

Which of the following statements is true?

A) The carbonyl carbon in a carboxylic acid does not give a ¹³C signal in a ¹³C-NMR spectrum.
B) The carbonyl carbon in a carboxylic acid gives a ¹³C signal in the same region as a carbonyl carbon from a ketone or aldehyde - in the range of 200 ppm.
C) The carbonyl carbon of a carboxylic acid splits a proton signal into a doublet in an H-NMR spectrum.
D) The carbonyl carbon in a carboxylic acid gives a ¹³C signal in the same region as a carbonyl carbon from an ester or amide in the range of 150 to 180 ppm.
E) The carbonyl carbon in a carboxylic acid cannot be distinguished from an aromatic carbon because they both give signals in the range of 110 to 130 ppm.

Question 61

Propose a reasonable synthetic route to prepare cyclohexylacetic acid from methylenecyclohexane.

Question 62

Draw a Fischer projection of the product which results when (R)-2-bromobutane is treated with the following sequence of reagents:

and

Question 63

Provide the major organic product of the following reaction.

Question 64

Using the carboxylic acid below as your only carbon source, how would you make the given amide?

Question 65

Provide the major organic product of the reaction shown below.

Question 66

Provide the major organic product of the following reaction.

Question 67

Suggest a sequence of synthetic steps through which phenylacetic acid can be prepared from toluene via phenylacetonitrile.

Question 68

Suggest a sequence of synthetic steps through which p-toluic acid can be prepared from toluene.

Question 69

What two alkenes, which contain only one double bond, yield exclusively propanoic acid upon oxidation with hot concentrated KMnO₄?

Question 70

Provide the major organic product of the reaction shown below.

Question 71

Hept-3-yne yields what acids upon treatment with concentrated permanganate of ozone followed by water?

Question 72

Suggest a sequence of synthetic steps through which phenylacetic acid can be prepared from toluene and in which Grignard chemistry is employed.

Question 73

Provide the major organic product of the reaction shown below.

Question 74

Provide the sequence of reagents needed to accomplish the conversion below.

Question 75

Show how you could make the acid shown below starting with any alcohol:

Question 76

An unknown alkyne was subjected to concentrated KMnO₄ and only one product was isolated. The spectral information for 1H NMR of the product is given below.
δ (ppm) = 11.0 (1H, broad s), 2.39 (2H, q), 1.16 (3H, t)
What is the structure of the starting alkyne?

Question 77

Provide the major organic product of the following reaction sequence.

Question 78

Show how you could convert benzene to benzoic acid.

Question 79

Which sequence of steps below describes the best synthesis of 5-oxohexanoic acid starting with 1-methylcyclopentan-1-ol?

A) 1. Conc. KMnO₄
2) Dry gaseous HBr
3) mg/ether
4) CO₂
B) 1. H₂SO₄ and heat
2) Conc. KMnO₄
C) 1. Conc. KMnO₄
2) CH₃MgBr/ ether
_3. H₃O⁺
D) 1. H₂SO₄ and heat
2) O₃
3) (CH₃)₂S
4) PCC
E) 1. H₂SO₄ and heat
2) Conc. KMnO₄
3) LiAlH₄
4) H₃O⁺

Question 80

Provide the major organic product of the following reaction sequence.