Deck 19: Carboxylic Acids and the Acidity of the O-H Bond

Question 1

Why is the C-O single bond of a carboxylic acid shorter than the C-O single bond of an alcohol?

A) The carbon in the alcohol is sp² hybridized and has a higher percent s-character that lengthens the C-O bond in the alcohol.
B) The carbon in the carboxylic acid is sp³ hybridized and has a lower percent s-character that shortens the C-O bond in the carboxylic acid.
C) The carbon in the carboxylic acid is sp hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid.
D) The carbon in the carboxylic acid is sp² hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid.

Answer 1

The carbon in the carboxylic acid is sp² hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid.

Question 2

Arrange the following compounds in order of increasing boiling point, putting the compound with the lowest boiling point first.

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

Answer 2

I < IV < II < III

Question 3

What is the correct IUPAC name of the following compound?

A) 3,5,5-Trimethylcyclohexanecarboxylic acid
B) 3,3,5-Trimethylcyclohexanecarboxylic acid
C) 3,3,5-Trimethylcyclohexanoic acid
D) 3,5,5-Trimethylcyclohexanoic acid

Answer 3

3,3,5-Trimethylcyclohexanecarboxylic acid

Question 4

What is the common name of the following compound?

A) ",-Dimethyl--fluorobutyric acid"
B) "-Fluoro-,-dimethylbutyric acid"
C) "-Fluoro-,,-trimethylpropionic acid"
D) "-Fluoro-,,-trimethylbutyric acid"

Question 5

What is the common name of the following compound?

A) Propanedioic acid
B) 1,3-propanedicarboxylic acid
C) Malonic acid
D) Succinic acid

Question 6

Arrange the following compounds in order of decreasing water solubility, putting the most soluble compound first.

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

Question 7

Which of the following is the most polar organic compound?

A) CH₃CH₂CH₂CH₃
B) CH₃CH₂CHO
C) CH₃CH₂CH₂OH
D) CH₃COOH

Question 8

What is the correct IUPAC name of the following compound?

A) 2-Methoxypentanoic acid
B) 2-Methoxybutanoic acid
C) 4-Methoxybutanoic acid
D) 4-Methoxypentanoic acid

Question 9

What two groups make up the carboxylic acid group (RCOOH)?

A) Carbon dioxide and hydrogen
B) Carbonyl and hydroxyl
C) Carbon monoxide and hydroxyl
D) Carbonyl oxide and hydrogen

Question 10

What is the common name of the following compound?

A) ",-Dimethoxyvaleric acid"
B) "2,3-Dimethoxyvaleric acid"
C) "2,3-Dimethoxycaproic acid"
D) ",-Dimethoxycaproic acid"

Question 11

What two strong absorptions are characteristic of the IR spectrum of carboxylic acids?

A) A C=O absorption at 1710 cm^-1 and a C-H absorption at 3000 cm^-1.
B) A C=O absorption at 1710 cm^-1 and an O-H absorption at 2500-3500 cm^-1.
C) A C=O absorption at 1600 cm^-1 and an O-H absorption at 2500-3000 cm^-1.
D) A C-O absorption at 1500 cm^-1 and an O-H absorption at 2500-3500 cm^-1.

Question 12

What is the correct IUPAC name of the following compound?

A) (E)-2-Hexenoic acid
B) (Z)-2-Hexenoic acid
C) (E)-4-Hexenoic acid
D) (Z)-4-Hexenoic acid

Question 13

Arrange the following compounds in order of increasing water solubility, putting the least soluble compound first.

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

Question 14

Which of the following is the structure of oxalic acid?

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

Question 15

Which of the following is the correct IUPAC name for the following structure?

A) Potassium propanoate
B) Butanoic potassium
C) Potassium propanoic
D) Potassium butanoate

Question 16

What is the correct IUPAC name of the following compound?

A) 2-sec-Butyl-4,4-dimethylnonanoic acid
B) 4,4-Dimethyl-2-isobutylnonanoic acid
C) 4,4-Dimethyl-2-sec-butylnonanoic acid
D) 2-Isobutyl-4,4-dimethylnonanoic acid

Question 17

What is the correct IUPAC name of the following compound?

A) 4-Isopropyl-3-methylbutanoic acid
B) 2,4-Dimethylhexanoic acid
C) 3,5-Dimethylhexanoic acid
D) 3,5-Dimethy-1-hexanoic acid

Question 18

What is the common name of the following compound?

A) "-Methylbutyric acid"
B) "-Propylpropionic acid"
C) "-Methylvaleric acid"
D) "-Methylcaproic acid"

Question 19

What is the hybridization of the carbon atom in a carboxy group?

A) sp
B) sp²
C) sp³
D) p

Question 20

What is the correct IUPAC name of the following compound?

A) 3,4-Dimethylcyclohexanoic acid
B) 3,4-Dimethylcyclohexanecarboxylic acid
C) 4,5-Dimethylcyclohexanecarboxylic acid
D) 1,2-Dimethylcyclohexanecarboxylic acid

Question 21

Arrange the following compounds in order of increasing acidity, putting the least acidic first.

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

Question 22

Rank the following compounds in order of increasing acidity, putting the least acidic first.

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

Question 23

Which of the following structures is the major contributor to the resonance hybrid of the phenoxide anion?

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

Question 24

Why is pure acetic acid often called glacial acetic acid?

A) Because it freezes just below 0°C, forming white crystals.
B) Because it freezes just below 100°C, forming white crystals.
C) Because it freezes just below room temperature, forming white crystals.
D) Because it freezes just above room temperature, forming white crystals.

Question 25

Rank the following compounds in order of decreasing acidity, putting the most acidic first.

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

Question 26

Which of the following cannot be the starting material for the following reaction?

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

Question 27

Which of the following bases are strong enough to significantly deprotonate ethanol, CH₃CH₂OH (pKa = 16)?

A) NaOCH₃
B) NaOH
C) NaH
D) NaOCH₂CH₃

Question 28

Where do the two noteworthy peaks of carboxylic acids appear in ¹HNMR spectra?

A) Between 10 and 12 ppm for the OH proton and 2-2.5 ppm for the protons on the  carbon to the carboxy group.
B) Between 6 and 9 ppm for the OH proton and 2-2.5 ppm for the protons on the  carbon to the carboxy group.
C) Between 10 and 12 ppm for the OH proton and 1-1.5 ppm for the protons on the  carbon to the carboxy group.
D) Between 6 and 9 ppm for the OH proton and 1-1.5 ppm for the protons on the  carbon to the carboxy group.

Question 29

What is the other product formed in the oxidation of the following terminal alkyne?

A) HCOOH
B) HCOH
C) CO₂
D) CO

Question 30

What would happen if a mixture of benzoic acid (C₆H₅COOH) and NaCl is added to a separatory funnel containing H₂O and CH₂Cl₂?

A) The benzoic acid would dissolve in the water layer and the NaCl would dissolve in the organic layer.
B) The benzoic acid would dissolve in the organic layer and the NaCl would dissolve in the water layer.
C) Both benzoic acid and NaCl would dissolve in the organic layer.
D) Both benzoic acid and NaCl would dissolve in the water layer.

Question 31

Rank the following compounds in order of increasing acidity, putting the least acidic first.

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

Question 32

Rank the following compounds in order of decreasing acidity, putting the most acidic first.

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

Question 33

Which of the following reagents can accomplish the transformation below?

A) PCC, CH₂Cl₂
B) [1] LiAlH₄, THF; [2] H₂O
C) [1] O₃; [2] H₂O
D) K₂Cr₂O₇, H₂SO₄, H₂O

Question 34

In the presence of strong acids, which of the oxygen atoms on the carboxyl group is preferentially protonated and why?

A) Protonation occurs at the carbonyl oxygen because the resulting conjugate acid is stabilized by resonance.
B) Protonation occurs at the carbonyl oxygen because the resulting conjugate base is stabilized by the inductive effect.
C) Protonation occurs at the hydroxyl oxygen because the resulting conjugate acid is stabilized by resonance.
D) Protonation occurs at the hydroxyl oxygen because the resulting conjugate base is stabilized by the inductive effect.

Question 35

Rank the following compounds in order of increasing acidity, putting the least acidic compound first.

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

Question 36

Rank the labeled protons (H_a-H_d) in order of increasing acidity, starting with the least acidic.

A) Ha < Hb < Hc < Hd
B) Hb < Hc < Ha < Hd
C) Hd < Ha < Hc < Hb
D) Hb < Hc < Hd < Ha

Question 37

What physical property and reaction type are used by extraction as useful techniques to separate and purify mixtures of compounds?

A) Physical property = solubility differences; reaction type = acid-base reaction.
B) Physical property = boiling point; reaction type = acid-base reaction.
C) Physical property = solubility differences; reaction type = oxidation-reduction.
D) Physical property = density; reaction type = oxidation-reduction.

Question 38

Rank the following compounds in order of increasing acidity, putting the least acidic first.

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

Question 39

Rank the following compounds in order of decreasing acidity, putting the most acidic first.

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

Question 40

What would happen if a mixture of benzoic acid and cyclohexanol dissolved in CH₂Cl₂ is treated with aqueous NaOH solution?

A) Benzoic acid would remain in the CH₂Cl₂ layer, and cyclohexanol would dissolve in the aqueous layer.
B) Benzoic acid would dissolve in the aqueous layer while cyclohexanol would remain in the CH₂Cl₂ layer.
C) The salt of benzoic acid would dissolve in the aqueous layer while cyclohexanol would remain in the CH₂Cl₂ layer.
D) The salt of benzoic acid would remain in the CH₂Cl₂ layer while cyclohexanol would dissolve in the aqueous layer.

Question 41

What is the overall charge of the amino acid, alanine, at pH = 10?

A) + 1
B) - 1
C) No overall charge
D) - 2

Question 42

As applied to the chemistry of amino acids, what is the definition for the isoelectric point?

A) The pH at which the amino acid exists primarily in its acidic form.
B) The pH at which the amino acid exists primarily in its basic form.
C) The pH at which the amino acid exists as a mixture of isomers.
D) The pH at which the amino acid exists primarily in its neutral form.

Question 43

What is the overall charge of the amino acid, alanine, at pH = 7?

A) + 1
B) - 1
C) No overall charge
D) + 2

Question 44

What is the overall charge of the amino acid, alanine, at pH = 2?

A) + 1
B) - 1
C) No overall charge
D) + 2