1 A Uhcl Orgo Ii Exam3.0 Questions Ch20

Front 1

1) 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

Back 1

D) carboxyl

Front 2

2) The common name for pentanedioic acid is:
A) pimelic acid
B) oxalic acid
C) glutaric acid
D) succinic acid
E) adipic acid

Back 2

C) glutaric acid

Front 3

3) 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.

Back 3

C) form stable hydrogen-bonded dimers.

Front 4

4) 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

Back 4

A) resonance stabilization of the carboxylate ion

Front 5

6) Which of the following is the strongest acid?
A) acetic acid
B) chloroacetic acid
C) bromoacetic acid
D) fluoroacetic acid

Back 5

D) fluoroacetic acid

Front 6

7) Which of the following is the strongest acid?
A) chloroacetic acid
B) dichloroacetic acid
C) trichloroacetic acid
D) acetic acid

Back 6

C) trichloroacetic acid

Front 7

8) 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

Back 7

A) 2,2-dichlorobutanoic acid

Front 8

9) 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

Back 8

A) p-nitrobenzoic acid

Front 9

10) Which of the following is the strongest acid?
A) (CH3)2CHCO2H
B) CH3CH2CO2H
C) CH3OCH2CO2H
D) PhCH2CO2H
E) O2NCH2CO2H

Back 9

E) O2NCH2CO2H

Front 10

11) Which of the following statements is true?
At two pH units ----- the pKa, the carboxylate ion concentration exceeds the concentration of the carboxylic acid
A) --- above --- by a 100 to 1 ratio.
B) --- above --- by a 2 to 1 ratio.
C) --- below --- by a 2 to 1 ratio.
D) --- below --- by a 10 to 1 ratio.
E) --- below --- is equal to the carboxylic acid concentration.

Back 10

A) At two pH units above the pKa, the carboxylate ion concentration exceeds the concentration of the carboxylic acid by a 100 to 1 ratio.

A) --- above --- exceeds the concentration of the carboxylic acid by a 100 to 1 ratio.

Front 11

12) At pH 4.5, which of the following acids would be most dissociated?
A) p-nitrobenzoic acid (pKa = 3.41)
B) acetic acid (ethanoic acid) (pKa = 4.74)
C) hexanoic acid (pKa = 4.88)
D) octanoic acid (pKa = 4.89)

Back 11

A) p-nitrobenzoic acid (pKa = 3.41)

Front 12

13) An unknown compound is insoluble in water but dissolves in 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

Back 12

A) a carboxylic acid

Front 13

14) 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

Back 13

C) B + C

Front 14

15) 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.

Back 14

C) Extraction with aqueous NaHCO3.

Front 15

16) In the propanoate ion,:
A) both the carbon-oxygen bonds are the same length.
B) the carbon-oxygen double bond is shorter.
C) the carbon-oxygen double bond is longer.
D) one of the oxygen atoms bears a -1 charge.
E) the carbon atom bears a -1 charge.

Back 15

A) both the carbon-oxygen bonds are the same length.

Front 16

17) 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

Back 16

B) δ 10 - 13 ppm

Front 17

18) Which of the following statements is true?
The carbonyl C in a -COOH ---
A) --- does not give a 13C signal in a 13C-NMR spectrum.
B) --- gives a 13C signal in the same region as a carbonyl C from a ketone or aldehyde ~ 200 ppm.
C) --- splits a proton signal into a doublet in an H-NMR spectrum.
D) --- gives a 13C signal in the same region as a carbonyl C from an ester or amide ~ 150-180 ppm.
E) --- cannot be distinguished from an aromatic C because both give signals of ~ 110-130 ppm.

Back 17

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.

Front 18

19) In the mass spectrum of pentanoic acid, the base peak occurs at m/z:
A) 102
B) 101
C) 85
D) 73
E) 60

Back 18

E) 60

Front 19

20) 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

Back 19

E) carbon dioxide

Front 20

21) 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

Back 20

D) (CH3)3CCO2H

Front 21

22) 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

Back 21

D) 4-oxocyclohexanecarboxylic acid

Front 22

23) 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

Back 22

B) adipic acid

Front 23

24) What compound is produced when (CH3)2CHCH2Br is subjected to the following sequence of steps: 1. Mg, Et2O, 2. CO2, 3. H3O+?
A) 2-methylpropanoic acid
B) 3-methylpropanoic acid
C) 2-methylbutanoic acid
D) 3-methylbutanoic acid
E) 2-methylhexanoic acid

Back 23

D) 3-methylbutanoic acid

Front 24

26) 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+

Back 24

B) 1. H2SO4 and heat
2. Conc. KMnO4

Front 25

27) Which of the following conditions will drive the equilibrium of the Fischer esterification towards ester formation?
A) addition of water
B) removal of water as it is formed
C) addition of an inorganic acid as a catalyst
D) removal of alcohol

Back 25

B) removal of water as it is formed

Front 26

28) The methyl ester of a carboxylic acid can be synthesized directly using:
A) SOCl2
B) PCl5
C) C2O2Cl2
D) CH2N2
E) CH3NH2

Back 26

D) CH2N2

Front 27

29) Which of the following reactions involves the formation of a methyl ester from a carboxylic acid?
A) Cope elimination
B) Hell-Volhard-Zelinsky reaction
C) reaction with CH2N2
D) Hunsdiecker reaction
E) hydroboration with diborane

Back 27

C) reaction with CH2N2

Front 28

30) The first mechanistic step in the direct reaction of an amine with a carboxylic acid to produce an amide is:
A) an acid-base reaction
B) nucleophilic attack on the carbonyl carbon
C) loss of H2O
D) loss of CO2
E) loss of N2

Back 28

A) an acid-base reaction

Front 29

31) LiAl [OC(CH3)3]3H will reduce an acid chloride to an:
A) alcohol
B) alkane
C) acid
D) aldehyde
E) acetal

Back 29

D) aldehyde

Front 30

34) Lithium aluminum hydride reduces carboxylic acids to primary alcohols via what intermediate?
A) a ketone
B) a methyl ester
C) an aldehyde
D) a secondary alcohol
E) an acid chloride

Back 30

C) an aldehyde

Front 31

35) The conversion of butanoic acid to 2-pentanone is best accomplished with:
A) 1. thionyl chloride; 2. methylmagnesium bromide
B) methyllithium
C) 1. methanol, sulfuric acid; 2. methyllithium
D) 1. thionyl chloride; 2. methanol
E) 1. sulfuric acid; 2. methanol

Back 31

B) methyllithium

Front 32

36) What alkyllithium would react with acetic acid to form 2-butanone?
A) methyllithium
B) vinyllithium
C) ethyllithium
D) propyllithium
E) phenyllithium

Back 32

C) ethyllithium

Front 33

37) Esters and amides are most easily made by nucleophilic acyl substitution reactions on:
A) alcohols
B) acid anhydrides
C) carboxylates
D) carboxylic acids
E) acid chlorides

Back 33

E) acid chlorides

Front 34

38) Acid chlorides can be prepared from carboxylic acids by treatment with:
A) (COCl)2
B) SOCl5
C) KCl
D) NaCl

Back 34

A) (COCl)2

Front 35

39) Which of the following reagents can be used to convert a carboxylic acid directly into its corresponding acid chloride derivative?
A) (COCl)2
B) HCl
C) CH3Cl
D) NaOCl
E) CH3COCl

Back 35

A) (COCl)2

Front 36

5) 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

Back 36

B) 4 < 1 < 3 < 2 < 5

Front 37

25) 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+?

Back 37

Answer: b

Front 38

32) Which of the reagents listed below would work best in the following reaction?

A) NaBH4
B) LiAlH4
C) BH3 -THF
D) LiAl[(OC(CH3)3]3H
E) none of the above

Back 38

C) BH3 -THF

Front 39

33) Which of the following would be the preferred reagents used in the following synthesis?
A) 1. NaBH3-THF 2. H3O+
B) 1. Mg/ether 2. dry CO2 3. H3O+
C) 1. LiAlH4-THF 2. H3O+
D) 1. Hot KMnO4 2. H3O+
E) 1. LiAlH[O(CH3)3]3-THF 2. H3O+

Back 39

C) 1. LiAlH4-THF
2. H3O+