1 A Uhcl Orgo Ii Exam3.0 Questions Ch19

Front 1

1) Which of the following correctly describes the bond angle and hybridizations present in formaldehyde?
A) C, sp2; O, sp3; HCO, ~120°
B) C, sp2; O, sp2; HCO, ~120°
C) C, sp2; O, sp2; HCO, ~109.5°
D) C, sp3; O, sp2; HCO, ~109.5°
E) C, sp3; O, sp3; HCO, ~109.5°

Back 1

B) C, sp2; O, sp2; HCO, ~120°

Front 2

2) The double bond between carbon and oxygen is similar to an alkene C=C, except that C=O is:
A) shorter and weaker.
B) shorter and stronger.
C) longer and weaker.
D) longer and stronger.
E) longer.

Back 2

B) shorter and stronger.

Front 3

3) The positively polarized carbon atom of a carbonyl group acts as:
A) an electrophile and a Lewis base.
B) a nucleophile and a Lewis base.
C) an electrophile and a Lewis acid.
D) a nucleophile and a Lewis acid.
E) both a Lewis acid and a Lewis base.

Back 3

C) an electrophile and a Lewis acid.

Front 4

4) Another name for β-methoxybutyraldehyde is:
A) 2-methoxypropanal.
B) 3-methoxypropanal.
C) 2-methoxybutanal.
D) 3-methoxybutanal.
E) 2-methoxypentanal.

Back 4

D) 3-methoxybutanal.

Front 5

5) Which of the following represents the correct ranking in terms of increasing boiling point?
A) n-butane < 1-butanol < diethyl ether < 2-butanone
B) n-butane < 2-butanone < diethyl ether < 1-butanol
C) 2-butanone < n-butane < diethyl ether < 1-butanol
D) n-butane < diethyl ether < 1-butanol < 2-butanone
E) n-butane < diethyl ether < 2-butanone < 1-butanol

Back 5

E) n-butane < diethyl ether < 2-butanone < 1-butanol

Front 6

6) Which of the following compounds is most soluble in water?
A) acetone
B) cyclohexanone
C) 2-butanone
D) 3-butanone
E) benzophenone

Back 6

A) acetone

Front 7

7) In carbon NMR, the carbon atom of the carbonyl group in aldehydes and ketones has a chemical shift of about:
A) 20 ppm.
B) 40 ppm.
C) 60 ppm.
D) 120 ppm.
E) 200 ppm.

Back 7

E) 200 ppm.

Front 8

8) Which compound will show an intense peak in the mass spectrum at m/z 58?
A) CH3COCH2CH2CH3
B) (CH3)2CHCOCH3
C) CH3CH2COCH2CH3
D) (CH3)3CCHO
E) (CH3)3CCOCH3

Back 8

A) CH3COCH2CH2CH3

Front 9

9) In the mass spectrum of 3,3-dimethyl-2-butanone, the base peak will occur at m/z:
A) 43
B) 58
C) 84
D) 85
E) 100

Back 9

A) 43

Front 10

10) When a carbonyl is part of a conjugated π-network, the C=O stretch:
A) has a higher frequency than in a nonconjugated system.
B) has a lower frequency than in a nonconjugated system.
C) always occurs at 1710 cm-1.
D) occurs around 2700 cm-1.
E) cannot be distinguished from the C=O stretch in a nonconjugated system.

Back 10

B) has a lower frequency than in a nonconjugated system.

Front 11

11) In the proton NMR spectra of aldehydes and ketones, the protons bonded to carbons adjacent to the carbonyl group typically fall into which of the chemical shift ranges below?
A) 1.0-2.0 ppm
B) 2.0-3.0 ppm
C) 4.0-4.5 ppm
D) 7.0-8.0 ppm
E) 9.0-10.0 ppm

Back 11

B) 2.0-3.0 ppm

Front 12

12) The proton NMR spectrum of an unknown compound contains a triplet at 9.8 ppm. Which of the following could be this unknown?
A) (CH3)3CCHO
B) CH3CH2CH2CO2H
C) CH3CH2CH2CHO
D) CH3CO CH2Ph
E) PhCHO

Back 12

C) CH3CH2CH2CHO

Front 13

13) Which of the following compounds would show only one triplet in its off resonance decoupled 13C NMR spectrum?
A) acetone
B) butanal
C) pentanal
D) 2-pentanone
E) 3-pentanone

Back 13

E) 3-pentanone

Front 14

14) Which of the following transitions is usually observed in the UV spectra of ketones?
A) n to π*
B) n to π
C) σ to n
D) σ to σ*
E) n to σ*

Back 14

A) n to π*

Front 15

15) The strongest absorptions in the UV spectra of aldehydes and ketones are ones which result from __________ electronic transitions.
A) σ to σ*
B) σ to π*
C) n to π*
D) π to π*
E) π to σ*

Back 15

D) π to π*

Front 16

16) What name is given to the linear polymer which contains many formaldehyde units?
A) trioxane
B) formalin
C) paraformaldehyde
D) polyacetaldehyde
E) polyalal

Back 16

C) paraformaldehyde

Front 17

17) What reagent can be used to convert 2-methylbutan-1-ol into 2-methylbutanal?
A) LiAlH4
B) Na2Cr2O7
C) O3
D) KMnO4
E) PCC

Back 17

A) LiAlH4

Front 18

18) What reagents can be used to convert 1-hexyne into 2-hexanone?
A) 1. Sia2BH; 2. H2O2, NaOH
B) Hg2+, H2SO4, H2O
C) 1. O3; 2. (CH3)2S
D) 1. CH3MgBr; 2. CO2
E) 1. H2, Ni; 2. Na2Cr2O7, H2SO4

Back 18

B) Hg2+, H2SO4, H2O

Front 19

19) Oxidation of a 1° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above

Back 19

E) none of the above

Front 20

20) Oxidation of a 2° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above

Back 20

B) a ketone

Front 21

21) Oxidation of a 3° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above

Back 21

E) none of the above

Front 22

22) Oxidation of a 1° alcohol with pyridinium chlorochromate results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above

Back 22

C) an aldehyde

Front 23

24) Which of the following carbonyl compounds may be made from 1,3-dithiane?
1) methyl vinyl ketone 2) 2-pentanone 3) 3,3-dimethyl-2-butanone 4) 2-phenylethanal
A) 1 & 4
B) 2 only
C) 2 & 3
D) 2 & 4

Back 23

D) 2 & 4

Front 24

25) Treatment of a nitrile with a Grignard reagent followed by hydrolysis results in __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) an alcohol

Back 24

B) a ketone

Front 25

26) Which of the following describes a synthesis of an aldehyde?
A) hydrogenation of an acid chloride using Pd/BaSO4/S as a poisoned catalyst
B) reaction of a primary alcohol with Na2Cr2O7
C) reaction of a ketone with ozone
D) treatment of an alkene with Sia2BH
E) none of the above

Back 25

A) hydrogenation of an acid chloride using Pd/BaSO4/S as a poisoned catalyst

Front 26

27) Which series of reactions described below, if any, will result in the formation of 2-methylpentan-3-one starting with 1-propanol?
A) 1. (CH3)2CHMgBr/ diethyl ether 2. dilute H3O+ 3. PCC
B) 1. Na2Cr2O7/H2SO4 and heat 2. SOCl2 3. 2 (CH3)2CHMgBr/ diethly ether 4. H3O+
C) 1. Na2Cr2O7/H2SO4 and heat 2. (CH3)2CHMgBr/ diethyl ether 3. dilute H3O+ 4. LiAlH4
D) 1. PCC 2. (CH3)2CHLi/ diethyl ether 3. dilute H3O+ 4. Na2Cr2O7/H2SO4 and heat
E) none of the above

Back 26

D) 1. PCC
2. (CH3)2CHLi/ diethyl ether
3. dilute H3O+
4. Na2Cr2O7/H2SO4 and heat

Front 27

28) When the carbonyl group of a neutral ketone is protonated,:
A) the resulting species becomes more electrophilic.
B) the resulting species is activated toward nucleophilic attack.
C) subsequent nucleophilic attack on the resulting species is said to occur under acid-catalyzed conditions.
D) the resulting species has a positive charge.
E) all of the above.

Back 27

E) all of the above.

Front 28

29) Consider the equilbrium of each of the carbonyl compounds with HCN to produce cyanohydrins. Which is the correct ranking of compounds in order of increasing Keq for this equilbrium?
A) H2CO < cyclohexanone < CH3CHO < 2-methylcyclohexanone
B) CH3CHO < 2-methylcyclohexanone < cyclohexanone < H2CO
C) cyclohexanone < 2-methylcyclohexanone < H2CO < CH3CHO
D) cyclohexanone < 2-methylcyclohexanone < CH3CHO < H2CO
E) 2-methylcyclohexanone < cyclohexanone < CH3CHO < H2CO

Back 28

E) 2-methylcyclohexanone < cyclohexanone < CH3CHO < H2CO

Front 29

30) The following compound has been found effective in treating pain and inflammation (J. Med. Chem. 2007, 4222). Which sequence correctly ranks each carbonyl group in order of increasing reactivity toward nucleophilic addition?
A) 1 < 2 < 3
B) 2 < 3 < 1
C) 3 < 1 < 2
D) 1 < 3 < 2

Back 29

B) 2 < 3 < 1

Front 30

31) Rank the following compounds in order of their propensity to become a hydrate in water (ie, start with the least easy to hydrate: CH3COCH2CH3, H2CO, Cl3CCHO, and CH3CH2CHO.
A) CH3CH2CHO < CH3COCH2CH3 < H2CO < Cl3CCHO
B) CH3CH2CHO < H2CO < CH3COCH2CH3 < Cl3CCHO
C) CH3COCH2CH3 < H2CO < CH3CH2CHO < Cl3CCHO
D) CH3COCH2CH3 < CH3CH2CHO < H2CO < Cl3CCHO

Back 30

D) CH3COCH2CH3 < CH3CH2CHO < H2CO < Cl3CCHO

Front 31

32) An ylide is a molecule that can be described as a:
A) carbanion bound to a negatively charged heteroatom.
B) carbocation bound to a positively charged heteroatom.
C) carbocation bound to a carbon radical.
D) carbocation bound to a diazonium ion.
E) carbanion bound to a positively charged heteroatom.

Back 31

E) carbanion bound to a positively charged heteroatom.

Front 32

33) Which of the following is also known as a Schiff base?
A) an imine
B) a cyanohydrin
C) a hydrate
D) sodium hydroxide
E) an aldehyde

Back 32

A) an imine

Front 33

34) Acetals will react with:
A) H3O+
B) NaOCH3
C) PhLi
D) CH3CH2MgBr
E) NaBH4

Back 33

A) H3O+

Front 34

36) Why do acetal-forming reactions that use ethylene glycol have more favorable equilbrium constants than those using methanol?
A) Ethylene glycol reacts more rapidly.
B) They are more favorable on entropy grounds.
C) They are more favorable on enthalpy grounds.
D) Ethylene glycol is acidic and catalyzes the reaction.
E) The ethylene acetal can serve as a protecting group.

Back 34

B) They are more favorable on entropy grounds.

Front 35

38) What intermediate occurs when a ketone undergoes a Wolff-Kishner reduction?
A) a cyanohydrin
B) a hydrated aldehyde
C) a carboxylate
D) a semicarbazone
E) a hydrazone

Back 35

E) a hydrazone

Front 36

39) The reagent which converts a carbonyl group of a ketone into a methylene group is:
A) Na, NH3, CH3CH2OH
B) LiAlH4
C) NaBH4, CH3CH2OH
D) Zn(Hg), conc. HCl
E) LiAlH[OC(CH3)3]3

Back 36

D) Zn(Hg), conc. HCl

Front 37

23) Which of the following reactions will not yield a ketone product?

Back 37

A)

Front 38

35) What would be the product of the following reaction?

Back 38

A)

Front 39

37) RxNs forming A from B?
A) 1. HO-(CH2)2-OH /trace H3O+ 2. DMSO (COCl2)/Et3N, CH2Cl2 3. MgBr-(CH2)2-CH3/diethylether 4. H3O+
B) 1. PCC 2. SOCl2 3. LiCu-((CH2)2-CH3)2 4. H3O+
C) 1. Na2Cr2O7/H2SO4 2. SOCl2 3. 2 MgBr-(CH2)2-CH3/diethylether 4. H3O+
D) both A and B
E) both B and C

Back 39

A) 1. HO-(CH2)2-OH /trace H3O+
2. DMSO (COCl2)/Et3N, CH2Cl2
3. MgBr-(CH2)2-CH3/diethylether
4. work-up with H3O+