ch10-ques-2012

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Chapter 10 Multiple Choice Questions:

Topic: Introduction to Alkynes Section: 10.1

Difficulty Level: Easy

1. For the molecule below, known as 2-pentyne, which of the following describes the orbital overlap of the C2—C3 sigma bond?

C C CH3 CH2CH3 A) sp–sp B) sp2–sp2 C) sp3–sp3 D) p–p E) sp3–sp Ans: A

2. For the molecule below, known as 2,4-hexadiyne, which of the following describes the orbital overlap of the C3—C4 sigma bond?

H₃C C C C C CH₃ A) sp–sp B) sp2_–sp2 C) sp3–sp3 D) p–p E) sp3_–sp Ans: A

3. The sigma bond of an alkyne is formed from the overlap of which orbitals? A) sp3–sp3 B) p–p C) sp2–sp2 D) s–s E) sp–sp Ans: E

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4. What is the hybridization of the carbon atoms numbered 1 and 2 respectively in the following structure? C C C C H H H _{1 2} A) sp3_{, sp}2 B) sp2, sp2 C) sp, sp D) sp2, sp E) sp, sp2 Ans: D

5. The C≡C bond of an alkyne is composed of which bond types? A) three anti-bonds

B) three σ bonds

C) two σ bonds and one π bond D) one σ bond and two π bonds E) three π bonds

Ans: D

6. Which of following statements best describes the general reactivity of alkynes? A) An alkyne reacts as a nucleophile, and is therefore electron rich. B) An alkyne reacts as a nucleophile, and is therefore electron poor. C) Alkynes fail to undergo electrophilic addition reactions, unlike alkenes. D) An alkyne reacts as an electrophile, and is therefore electron rich. E) An alkyne reacts as an electrophile, and is therefore electron poor. Ans: A

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Difficulty Level: Moderate

7. Which of the following statements is true about propyne, H–C≡C–CH3?

A) It contains 3 sigma bonds. B) It contains three pi bonds.

C) The H–C≡C bond angle is about 109.5°. D) The C≡C–C bond angle is 180°.

E) All carbon-carbon bonds are of equal length. Ans: D

Topic: Nomenclature of Alkynes Section: 10.2

8. What is the correct IUPAC name for the molecule shown below?

H2C C C CH2 C Br CH3 CH3 H3C A) 6-Bromo-3-octyne B) 6-Bromo-6-methyl-3-heptyne C) 2-Bromo-2-methyl-4-heptyne D) 6-Bromo-6,6-dimethyl-3-hexyne E) 2-Bromo-4-octyne Ans: B

C CH CH2CH3 CH2CH3 C CH3CH2 A) 1,1-Diethyl-2-pentyne B) 3-(1-Butynyl)pentane C) 5-Ethyl-3-octyne D) 3-Ethyl-4-heptyne E) 5-Ethyl-3-heptyne Ans: E

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10. What is the correct IUPAC name for the molecule shown below? C CH CH2CH2CH3 CH2CH3 C HC H3C H3C A) 2-Methyl-5-propyl-3-heptyne B) 5-Ethyl-2-methyl-3-octyne C) 1-Isopropyl-3-ethyl-1-hexyne D) 6-Methyl-3-propyl-4-heptyne E) 4-Ethyl-7-methyl-5-octyne Ans: B

C C H3C CH3 CH3 H C C H₃C CH3 A) 2,2,3-Trimethyl-4-hexyne B) 4-tert-Butyl-2-pentyne C) 4,5,5-Trimethyl-2-hexyne D) 4,5,5,5-Tetramethyl-2-pentyne E) 2,2-Dimethyl-3-(1-propynyl)butane Ans: C

A) 5,6,6-Trimethyl-1-heptyne B) 5-tert-Tutyl-1-hexyne C) 2,2,3-Trimethyl-6-heptyne D) 2,2,3-(3-Butynyl)butane E) sec-Butyl-tert-butylacetylene Ans: A

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Cl Cl Cl A) 1,1,1-Trichloro-4-hexyne B) 4,4,4-Trichloro-1-butyne C) 1,1,1-Trichloro-2-butyne D) 5,5,5-Trichloro-2-pentyne E) 6,6,6-Trichloro-2-hexyne Ans E

A) 4,4-Dimethyl-2-pentyne B) 2,2-Dimethyl-4-heptyne C) 1-tertButyl-3-heptyne D) 6,6-Dimethyl-3-heptyne E) 6,6,6-Trimethyl-3-hexyne Ans: D

A) 4-Ethyl-2-pentyne B) 2-Ethyl-3-pentyne C) 3-Methyl-4-hexyne D) 4-Methyl-2-hexyne E) sec-Butylpropyne Ans: D

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16. Which of the following is an acceptable structure for hepta-3,6-dien-1-yne?

I II III IV V A) I B) II C) III D) IV E) V Ans: A

17. Which of the following is an acceptable structure for 2-hexyne?

I II III IV V A) I B) II C) III D) IV E) V Ans: D

18. Which of the following is an acceptable structure for 3-sec-butyl-1-heptyne?

I II III IV V A) I B) II C) III D) IV E) V Ans: B

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19. Provide the systematic IUPAC name for BrCH2CH2C≡CCH2CH3.

A) 1-Bromo-3-hexyne B) 6-Bromo-3-hexyne C) 1-Bromo-2-hexyne D) 6-Bromo-4-hexyne E) 1-Bromo-4-hexyne Ans: A

20. Provide the systematic IUPAC name for HC≡CCH2CH2CH3.

A) Pentyne B) 1-Pentyne C) Butyne D) 1-Butyne E) 2-Butyne Ans: B

21. Provide the systematic IUPAC name for Cl3CCH2CH2CH2C≡CH.

A) 6,6,6-Trichloro-1-hexyne B) 1,1,1-Trichloro-5-hexyne C) 5,5,5-Trichloro-1-pentyne D) 1-Heptyne E) Trichlorobutylacetylene Ans: A

22. Provide the systematic IUPAC name for Cl3C(CH2)4C≡CH.

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B) 1,1,1-Trichloro-6-heptyne C) 1,1,1-Trichloro-5-heptyne D) 6,6,6-Trichloro-1-hexyne E) 7,7,7-Trichloro-1-heptyne Ans: E

23. Provide the systematic IUPAC name for (CH3)2CHC≡CCH2C(CH3)3.

A) 1,1,5,5,5-Pentamethyl-2-pentyne B) 1,1,1,5,5-Pentamethyl-3-pentyne C) 2,2,6-trimethyl-4-heptyne D) 2,6,6-trimethyl-3-heptyne E) tert-butylisopropylacetylene Ans: D

24. Provide the systematic IUPAC name for the molecule below: CH3C(CH3)2CH2C≡CCH2CH(CH2CH3)CH3 A) 2,7,7-Trimethyl-5-nonyne B) 2-Ethyl-7,7-dimethyl-4-octyne C) 2,2,7-Trimethyl-4-nonyne D) 7-Ethyl-2,2-trimethyl-4-octyne E) 6-Undecyne Ans: C

Br

A) 3-Bromo-4-acetylenyl-heptane B) 3-(1-Bromopropyl)-1-hexyne C) 3-Bromo-4-propyl-5-hexyne D) 4-Bromo-3-propyl-1-hexyne

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E) 4-Ethynyl-5-bromo-heptane Ans: D

26. Which of the following is an acceptable structure for (R)-5-bromohept-2-yne.

I II III IV V Br Br Br Br Br A) I B) II C) III D) IV E) V Ans: E

A) (E)-5-methyl-5-hepten-1-yne B) (Z)-5-methyl-5-hepten-1-yne C) (E)-3-methyl-2-hepten-6-yne D) (Z)-3-methyl-2-hepten-6-yne E) (E)-2-butynyl-2-butene Ans: A

A) (E)-4-isopropyloct-3-en-5-yne B) (Z)-4-isopropyloct-3-en-5-yne C) (E)-5-isopropyloct-5-en-3-yne

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D) (Z)-5-isopropyloct-5-en-3-yne E) (E)-4-(2-methylethyl)oct-3-en-5-yne Ans: B

29. Which structure shown below represents (Z)-3,5-dichloro-3-hexen-1-yne?

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

E) I and II are both correct Ans: B

30. Which of the following is an acceptable structure for (2E,4E)-octa-2,4-dien-6-yne?

I II III IV V A) I B) II C) III D) IV E) V Ans: D

31. Which of the following is an acceptable structure for octa-3,6-dien-1-yne? A) HC≡CCH=CHCH=CHCH2CH3

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C) CH3CH=CHCH2CH=CHC≡CH

D) CH3C≡CCH=CHCH=CHCH3

E) H2C=CHC≡CCH2CH=CHCH3

Ans: C

32. Which of the following is an acceptable structure for 2,5,5-trimethylhept-3-yne A) (CH3CH2)CH(CH3)C≡CCH2CH(CH3)2 B) (CH3CH2)C(CH3)2C≡CCH(CH3)2 C) (CH3CH2)2C(CH3)C≡CCH2CH3 D) CH3CH2C(CH3)2C≡CC(CH3)3 E) (CH3CH2CH2)CH(CH3)C≡CC(CH3)3 Ans: B

Difficulty Level: Hard

Cl A) (R,Z)-4-chlorohept-5-en-2-yne B) (S,E)-4-chlorohept-5-en-2-yne C) (S,E)-4-chlorohept-2-en-5-yne D) (R,E)-4-chlorohept-5-en-2-yne E) (R,E)-4-chlorohept-2-en-5-yne Ans: E

34. What is the correct IUPAC name for diisobutylacetylene? A) Diisopropylbutyne B) 2,7-Dimethyl-4-octyne C) 3,6-Dimethyl-4-octyne D) 2,5-Diethyl-3-hexyne E) 2,2,5,5-Tetramethyl-3-hexyne Ans: B

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35. What is the correct systematic IUPAC name for di-sec-butylacetylene? A) 2-Ethyl-5-methyl-3-heptyne B) 2,7-Dimethyl-4-octyne C) 3,6-Dimethyl-4-octyne D) 2,5-Diethyl-3-hexyne E) 2,2,5,5-Tetramethyl-3-hexyne Ans: C

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3

36. Rank the following carbanions, with the weakest base first, then by increasing base strength. HC C CH3CH2 I II III H2C CH A) I < II < III B) II < III < I C) III < II < I D) III < I < II E) II < I < III Ans: A

Difficulty Level:

37. Rank the following bases, with the strongest base first, then by decreasing basicity.

HC C CH3CH2O CH3CH2 H2N H2C CH I II III IV V A) III > I > V > II > IV B) III > V > IV > I> II C) V > I > III > II > IV D) III > IV > II > V > I E) IV > II > I > III > V Ans: B

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Section: 10.3

38. Rank the following acids, with the strongest acid first, then by decreasing acidity.

I II III IV V H2O H2C CH2 CH3CH3 HC CH NH3 A) V > I > IV > II > III B) III > IV > II > I > V C) V > I > III > II > IV D) I > IV > V > II > III E) IV > I > V > II > III Ans: D

39. Which of the circled hydrogen atoms is the most acidic?

I II III IV V H3C C C H H2C C H H C H H CH3 H3C C H CH3 CH3 H₃C C H H H H A) I B) II C) III D) IV E) V Ans: E

40. Sodium amide (NaNH2, sodamide) reacts with terminal alkynes in the role of the

A) Brønsted acid. B) Brønsted base. C) reducing agent. D) catalyst. E) electrophile. Ans: B

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41. Which of the bases below would quantitatively deprotonate a terminal alkyne? A) BuLi B) NH3 C) NaOH D) NaOCH2CH3 E) t-BuOK Ans: A

42. Which of the bases below would result in the greatest deprotonation of the alkyne, shown in the reaction below?

H₃C C C H ? H₃C C C

A) NaOCH2CH3 (sodium ethoxide)

B) t-BuONa (sodium tert-butoxide) C) NaH (sodium hydride)

D) NaHCO3 (sodium bicarbonate)

E) NaOH (sodium hydroxide) Ans: C

43. Which statement below best explains acetylene’s Ka being greater than ethylene’s?

A) Acetylide anions are resonance stabilized.

B) The 4 π electrons of the acetylide anion better stabilize a negative charge. C) The electronegativity of sp carbons being greater than sp2 carbons. D) The electronegativity of sp carbons being less than sp2 carbons. E) Acetylene has only two hydrogen atoms while ethylene has four. Ans: C

44. Select the best explanation for why methanol, CH3OH, cannot be used as a solvent

for the deprotonation of a terminal alkyne by sodium amide, NaNH2.

A) Sodium amide is not a strong enough base to deprotonate the alkyne. B) Sodium amide in methanol reduces alkynes to alkenes.

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D) Methanol is more acidic than the alkyne, and will be deprotonated instead. E) Methanol is toxic, and should be avoided when possible.

Ans: D

45. What are the products of the reaction shown below? CH3OH + CH3C≡C–Na+ → ? A) CH3C≡CCH3 + Na+OH– B) CH3C≡CH + CH3O–Na+ C) CH3C≡COCH3 + Na+OH– D) CH3OC≡CH + Na+CH3– E) no reaction Ans: B

46. The major result of treating 1-butyne with 6M aqueous NaOH would be: A) the production of the sodium acetylide.

B) the production of an alkene. C) the production of an alkane. D) the production of an enol.

E) nothing, as the alkyne would not react. Ans: E

47. Which of the circled hydrogen atoms is the least acidic?

I II III IV V H3C C C H H2C C H H C H H CH3 H₃C C H CH3 CH3 H3C C H H H H A) I B) II C) III D) IV E) V

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Ans: C

48. Of the species listed below, select those less basic than acetylide? A) BuLi B) NaNH2 C) NaOCH3 D) both A and C E) both B and C Ans: C

Topic: Preparation of Alkynes Section: 10.4

49. For the transformation shown below, select the expected major product.

Br Br xs NaNH₂ NH3 I II III IV V H C C CH2 NH₂ H2N A) I B) II C) III D) IV E) V Ans: D

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Br Br KOH Δ ? Br Br O Br I II III IV V A) I B) II C) III D) IV E) V Ans: B

51. For the reaction sequence below, select the expected major product.

1) Br2 2) 3 eq. NaNH2/NH3 3) H2O A) 3-methylhexane B) 1-bromo-3-methylhexene C) 2-bromo-3-methylhexene D) 3-methyl-1-hexyne E) 3-methyl-2-hexyne Ans: D

52. Treatment of 2,2-dibromobutane with molten KOH at 200°C would be expected to produce which of the following:

A) (E)-2-bromo-2-butene B) (Z)-2-bromo-2-butyne C) 1,2-butadiene D) 1-butyne E) 2-butyne Ans: D

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53. When preparing terminal alkynes by an elimination reaction, sodium amide

(NaNH2) dissolved in liquid ammonia (NH3) is used most frequently. Which of the

following statements offers the best explanation for the above statement?

A) The above statement is false; terminal alkynes are not produced under the given conditions.

B) Sodium amide deprotonates the terminal alkyne, driving formation of the alkynide ion.

C) Only sodium amide is a strong enough base to deprotonate a carbon. D) Terminal alkynes are more stable than the internal alkynes, and are always

the favored product.

E) Steric hindrance favors preparation of the less substituted terminal alkyne. Ans: B

Topic: Reduction of Alkynes Section: 10.5

54. For the reaction shown, select the expected major organic product.

I II III IV V ? H2 Pt A) I B) II C) III D) IV E) V Ans: C

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Na/NH3 I II III IV V ? A) I B) II C) III D) IV E) V Ans: B

I II III IV V ? H₂ Lindlar's cat. A) I B) II C) III D) IV E) V Ans: A

57. Reduction of 1 mole of (3E,5Z)-3-methylhepta-3,5-dien-1-yne will require how many moles of hydrogen (H2)?

A) 1 B) 2

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C) 3 D) 4 E) 5 Ans: D

58. Select the reagent(s) expected to accomplish the transformation shown below.

C C CH₃CH₂ CH₂CH₃ ? CH₃CH₂CH₂CH₂CH₃ A) H2, Ni B) H2, Ni2B C) Na, NH3(l) D) A and B E) B and C Ans: A

59. Select the best reagent expected to convert 3-heptyne to cis-3-heptene. A) NaNH2, NH3 B) Na, NH3 C) H2, Lindlar’s catalyst D) Both A and C E) Both B and C Ans: C

60. Which of the reagents below would convert 2-pentyne to trans-2-pentene? A) NaNH2, NH3 B) Na, NH3 C) H2, Lindlar’s catalyst D) H2, Pd/C E) H2O, HgSO4/H2SO4 Ans: B

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61. Select the best reagent to convert 3-heptyne to trans-3-heptene? A) Na/NH3 B) 1 eq. NaNH2, NH3 C) xs NaNH2, NH3 D) H2/Pt E) H2/Lindlar's catalyst Ans: A

C C H3CH2C CH2CH3 C C CH3CH2 CH2CH3 ? H H A) H2, Pd B) H2, Lindlar’s catalyst C) Na, NH3(l) D) A and B E) B and C Ans: C

63. Reaction of 3,4,5-trimethyl-4-hexen-1-yne with H2 and Pd/C will produce which of

the following compounds? A) 2,3,4-Trimethylhexane B) 3,4,5-Trimethylhexane C) 2,3,4-Trimethyl-1-hexene D) 3,4,5-Trimethyl-1-hexyne E) 2,3,4-Trimethyl-5-hexyne2 Ans: A

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64. Reaction of (3E,5Z)-3-methylhepta-3,5-dien-1-yne with H2 and Pd/C will produce

which of the compounds below? A) 1-sec-Butylbutane B) 2-Butylbutane2 C) 3-Methylheptane D) 3-Methyl-1-heptyne E) (3E,5Z)-3-Bethyl-1,3,5-heptatriene Ans: C

65. Of the reaction conditions provided below, which would be expected to convert 1 mole of 4-methyl-1-pentyne into 2-methylpentane?

A) H2, Lindlar’s catalyst B) Na, NH3(l) C) 2 moles of HCl D) 2 moles H2, Pt E) 1 mole H2, Pt Ans: D

66. Which reagents shown below would be expected to convert 2-pentyne to (Z)-2-pentene? A) H2, Pt B) Na, NH3 C) H2, Lindlar's catalyst D) Xs HCl E) HgSO4, H2O Ans: C

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67. For the reaction shown below, what is the IUPAC name of the expected product? ? Na NH3(l) A) 2-methylhexane B) (Z)-2-methyl-4-hexene C) (E)-2-methyl-4-hexene D) (Z)-5-methyl-2-hexene E) (E)-5-methyl-2-hexene Ans: E

C C CH2CH3 H3CH2C C C CH3CH2 CH2CH3 ? H H A) H2, Ni B) H2, Ni2B C) H2, Lindlar’s catalyst D) A and B E) B and C Ans: E

69. What is the expected major organic product from treatment of 4-methyl-2-pentyne with excess hydrogen in the presence of a platinum catalyst?

A) (E)-4-methyl-2-pentene B) (Z)-4-methyl-2-pentene C) 2-methylpentane D) 4-methylpentane

E) Equal mixture of A and B Ans: C

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70. What is the expected major organic product from treatment of 4-methyl-2-pentyne with hydrogen in the presence of Lindlar's catalyst?

A) (E)-4-methyl-2-pentene B) (Z)-4-methyl-2-pentene C) (E)-2-methyl-2-pentene D) (Z)-2-methyl-2-pentene E) 2-methylpentane Ans: B

71. What is the expected major organic product from treatment of 4-methyl-2-pentyne with sodium metal in liquid ammonia?

A) (E)-4-methyl-2-pentene B) (Z)-4-methyl-2-pentene C) (E)-2-methyl-2-pentene D) (Z)-2-methyl-2-pentene E) 2-methylpentane Ans: A

72. In the reaction between an alkyne and Na metal in liquid ammonia, Na’s role is as the: A) Brønsted acid. B) Brønsted base. C) reducing agent. D) catalyst. E) electrophile. Ans: C

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Difficulty Level: Modertate

73. In a dissolving metal reduction of an alkyne, a postulated intermediate is the trans alkenyl radical, shown below. In which orbital type would the unpaired electron be located? R H R A) sp B) sp2 C) sp3 D) p E) s Ans: B

74. For the reaction shown below, the resulting stereochemistry of the expected product is best described as:

H2 Pt A) only (S) B) only (R) C) racemic D) meso E) achiral Ans: E

75. Complete hydrogenation of a mixture of 1-octyne, 2-octyne, and 3-octyne, in the presence of a palladium catalyst, would produce how many distinct eight-carbon hydrocarbon products? A) 1 B) 2 C) 3 D) 6 E) 8 Ans: A

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76. For the reaction shown below, the resulting stereochemistry of the expected product is best described as:

H2 Ni2B (P-2) A) (R,E) B) (S,E) C) (R,Z) D) (S,Z) E) only (S) Ans: D

Topic: Hydrohalogenation of Alkynes Section: 10.6

77. Which of the compounds shown below would be the most likely product expected from the reaction scheme shown?

xs HCl ? Cl CH₃CH₂C CH Cl Cl Cl Cl I II III IV V Cl Cl Cl A) I B) II C) III D) IV E) V Ans: C

78. The expected major product from treatment of 1-pentyne with excess HBr in the presence of peroxides is:

A) 1-bromo-1-pentene B) 2-bromo-1-pentene C) 1,1-dibromopentane

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D) 2,2-dibromopentane E) 1,2-dibromopentane Ans: C

79. The expected major product from the treatment of 1-pentyne with 1 equivalent of HBr is: A) 1-bromo-1-pentene B) 2-bromo-1-pentene C) 1,1-dibromopentane D) 2,2-dibromopentane E) 1,2-dibromopentane Ans: B

80. The expected major product from the treatment of 1-pentyne with 2 equivalents of HBr is: A) 1-bromo-1-pentene B) 2-bromo-1-pentene C) 1,1-dibromopentane D) 2,2-dibromopentane E) 1,2-dibromopentane Ans: D

81. For the reaction below, select the structure of the expected major organic product.

1 eq HCl ? I II III IV V Cl Cl Cl Cl Cl

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A) I B) II C) III D) IV E) V Ans: C

82. What is the major expected product(s) of the reaction shown below?

C C CH3CH2 CH3 HCl ? A) 2,2-Dichloropentane B) 3,3-Dichloropentane C) 2,3-Dichloropentane D) A and B E) B and C Ans: D

1) 1 eq HCl 2) 1 eq HBr ? I II III IV V Br Cl Cl Br Br Cl _Br Cl Br Cl Cl Br A) I B) II C) III D) IV E) V Ans: D

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HBr ROOR ? (CH3)2CHCH2C CH Br Br Br Br Br Br I II III IV A) I and II B) III and IV C) II and III D) II and IV E) I and IV Ans: E

85. Select the expected major product(s) from the treatment of 1-pentyne with 1 equivalent of HBr in the presence of peroxides.

A) 2-Bromo-1-pentene B) (E)-1-Bromo-1-pentene C) (Z)-1-Bromo-1-pentene D) A and B E) B and C Ans: E

86. What mechanistic intermediate is used to explain the preference for addition of the Br atom, of HBr, to the internal carbon of a terminal alkyne?

A) Formation of a more stable primary vinylic carbocation. B) Formation of a more stable secondary vinylic carbocation. C) Addition of the H atom to the carbon already with an H. D) Addition of H, from HBr, to the least hindered carbon.

E) Steric hindrance for the approach of the Br atom to the primary carbon. Ans: B

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Topic: Hydration of Alkynes Section: 10.7

87. For the transformation shown, select the most appropriate reagent(s) to effect the change. ? (CH₃)₂CHCH₂CCH₃ O (CH3)2CHCH2C CH A) H2SO4, HgSO4 B) 1. Disiamylborane, 2. HO–, H2O, H2O2 C) K2Cr2O7, H+ D) NaOCl E) H2, Pd Ans: A

88. For the transformation shown, select the most appropriate reagent(s) to effect the change. ? (CH3)2CHCH2CH2CH (CH3)2CHCH2C CH O A) H2SO4, HgSO4 B) 1. Disiamylborane, 2. HO–, H2O, H2O2 C) K2Cr2O7, H+ D) NaOCl E) H2, Pd Ans: B

89. For the reaction shown, which of the compounds below would be the expected major, and final, organic product?

CH₃CH₂CH(CH₃)C CH HgSO₄ ? + H₂O H2SO4 I II III IV V O O O OH OH

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A) I B) II C) III D) IV E) V Ans: B

90. For the reaction shown, which of the compounds listed would be the expected major, and final, organic product?

H2O, H2SO4 HgSO4 ? I II III IV V O O O OH OH A) I B) II C) III D) IV E) V Ans: B

91. For the reaction shown, which of the compounds below would be the expected major organic product?

H2O, H2SO4 HgSO4 OH OH OH O O O HO OH I II III IV V ?

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A) I B) II C) III D) IV E) V Ans: C

? I II III IV V O O O OH OH 1) BH3•THF 2) H2O2, NaOH A) I B) II C) III D) IV E) V Ans: C

OH I II III IV V ? O OH O OH OH 1) BH3•THF 2) H₂O₂, NaOH A) I

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B) II C) III D) IV E) V Ans: C

? I II III IV V 1) Disiamylborane 2) H2O2, NaOH O O OH OH OH OH A) I B) II C) III D) IV E) V Ans: E

CH₃CH₂C(CH₃)₂C CH I II III IV V O O OH O OH ? 1) Disiamylborane 2) H₂O₂, NaOH A) I

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B) II C) III D) IV E) V Ans: C

96. For the reaction shown, which of the compounds listed would be the expected enol intermediate? H₂O, H₂SO₄ HgSO4 OH I II III IV V ? OH O OH OH OH OH A) I B) II C) III D) IV E) V Ans: A

97. For the reaction shown, which of the compounds below would be the expected enol intermediate? OH I II III IV V OH O OH OH OH OH ? 1) BH3•THF 2) H₂O₂, NaOH A) I

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B) II C) III D) IV E) V Ans: B

98. Which of the ketones below could not be prepared by an acid-catalyzed hydration of an alkyne? O O O O O I II III IV V A) I B) II C) III D) IV E) V Ans: D

99. Consider the list of alkyne addition reactions below, and select all those that involve an enol intermediate.

A) Hydroboration/oxidation

B) HgSO4 catalyzed hydration in dilute H2SO4

C) Hydrohalogenation D) Both A and B E) Both A and C Ans: D

100. In an acid-catalyzed hydration, which of the following alkynes is expected to produce a single ketone?

A) 2-decyne B) 3-decyne

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C) 4-decyne D) 5-decyne

E) All of the above will give a single product Ans: D

101. In an acid-catalyzed hydration, which of the following alkynes gives a single ketone? A) 2-pentyne B) 2-hexyne C) 2-heptyne D) 3-hexyne E) 3-heptyne Ans: D

102. For the reaction below, how many different organic products would be expected?

H2O, H2SO4 HgSO4 ? A) one B) two C) three D) four E) five Ans: B

103. Which of the following alkynes would give a single product under hydroboration-oxidation conditions?

A) 1-hexyne B) 2-hexyne C) 3-hexyne

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E) A and C would each give a single product Ans: E

104. Which of the alkynes below, after undergoing an acid-catalyzed hydration, would be expected to produce two different ketones in nearly equivalent yields?

A) 1-hexyne B) 2-hexyne C) 3-hexyne D) 3-methyl-1-pentyne E) 4-methyl-1-pentyne Ans: B

105. For the reaction shown, which of the compounds listed below would be the expected major, and final, organic product?

? I II III IV V 1) 9-BBN 2) H₂O₂, NaOH O O OH OH OH OH A) I B) II C) III D) IV E) V Ans: D

106. For the reaction below, which of the alkynes listed would be expected to produce the product under the conditions shown?

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I II III IV V 1) 9-BBN 2) H2O2, NaOH ? O A) I B) II C) III D) IV E) V Ans: C

107. What functional group would be expected to be found in the major, and final, organic product upon completion of the reaction between 1-hexyne and a mixture of mercuric sulfate and aqueous sulfuric acid?

A) aldehyde B) ketone C) diol D) ether E) carboxylic acid Ans: B

108. What functional group would be expected to be found in the major, and final, organic product upon completion of the reaction below.

? 1) 9-BBN 2) H2O2, NaOH A) aldehyde B) ketone C) diol D) enol E) alkene

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Ans: A

109. What is the expected functional group produced when cyclooctyne is reacted with disiamylborane, followed with treatment of basic hydrogen peroxide?

A) aldehyde B) ketone C) diol D) ether E) carboxylic acid Ans: B

110. Which of the reagents below, upon completion of reaction with a terminal alkyne, would be expected to produce an aldehyde as the final major organic product?

1) Disiamylborane 2) H2O2, NaOH 1) 9-BBN 2) H2O2, NaOH 1) BH3•THF 2) H2O2, NaOH H2O, H2SO4 HgSO4 I II III IV A) I and II B) II and III C) III and IV D) I, II and IV E) I, III and IV Ans: E

Topic: Halogenation of Alkynes Section: 10.8

111. What is the major product of the reaction shown below?

C C CH3CH2CH2 CH3 excess Cl2 ? CCl4 A) (E)-2,3-Dichloro-2-hexene B) (Z)-2,3-Dichloro-2-hexene C) 2,2-Dichlorohexane D) 3,3-Dichlorohexane E) 2,2,3,3-Tetrachlorohexane

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Ans: E

xs Cl2 ? Cl CH3CH2C CH Cl _Cl Cl Cl I II III IV V Cl Cl Cl Cl Cl Cl Cl A) I B) II C) III D) IV E) V Ans: E

113. Careful addition of 1 equivalent of Br2 to the alkyne shown below would be

expected to produce which of the following as the major organic product?

1 eq Br2 ? I II III IV V Br Br Br H Br Br Br Br CCl4 H Br Br Br Br Br A) I B) II C) III D) IV E) V Ans: B

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? (CH3)2CHCH(CH3)C Br Br Br Br I II III IV V CH excess Br2 CCl4 Br Br Br Br Br Br Br Br A) I B) II C) III D) IV E) V Ans: A

Topic: Halogenation of Alkynes (Hydrohalogenation…) Section: 10.8

115. The expected major product from treatment of 1-pentyne with excess HBr is: A) 1,1-dibromo-1-pentene B) 1,2-dibromo-1-pentene C) 1,1-dibromopentane D) 2,2-dibromopentane E) 1,1,2,2-tetrabromopentane Ans: D

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xs Br₂ ? I II III IV V Br Br Br Br Br Br Br Br Br Br Br BrBr A) I B) II C) III D) IV E) V Ans: D

117. Select the expected major product(s) from the treatment of 1-pentyne with 1 equivalent of Br2. A) 1,1-dibromo-1-pentene B) (E)-1,2-dibromo-1-pentene C) (Z)-1-bromo-1-pentene D) A and B E) B and C Ans: B

Topic: Ozonolysis of Alkynes Section: 10.9

118. Which of the following conditions effectively cleaves a carbon-carbon triple bond? A) HgSO4 and aqueous H2SO4

B) 1) Disiamylborane 2) H2O2, NaOH

C) H2, Lindlar’s catalyst

D) 1) O3 2) H2O

E) Na, NH3(l)

Ans: D

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119. Predict the major organic products of the reaction below. 1) O3 2) H2O O OH _O HO C O O O OH ? I II III IV A) I and II B) II an III C) I and IV D) II and III E) 1 and III Ans: C

120. For the reaction sequence shown, what are the expected major organic products?

1. O₃ 2. H2O I II III IV V O H O O OH O + + + + + O C OH H3C C O O H3C O OH HO O OH ? OH _O C O O H A) I B) II C) III D) IV E) V Ans: B

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Section: 10.9

121. What are the expected major products of the reaction sequence shown below?

1. O3 2. H2O ? I II III IV V O OH O HO O O C O O A) I and II B) I, III, and V C) II, III, and IV D) I and IV E) II, III, IV Ans: D

122. What is the expected major product of the reaction sequence shown below?

I II III IV V 1. O3 2. H2O ? O O CO2H CO2H CO₂H O O O O A) I B) II C) III D) IV E) V Ans: B

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moles of CO2 upon completion of the reaction? A) 1 B) 2 C) 3 D) 4 E) 8 Ans: C

124. Select the alkyne listed below that, upon treatment with ozone followed by water, would not produce carbon dioxide and a carboxylic acid as the final products?

A) Ethyne B) Propyne C) 1-Butyne D) 1-Pentyne E) 1-Hexyne Ans: A

125. Which of the following alkynes, upon ozonolysis, would be expected to produce only one major organic product?

A) 1-Hexyne B) 2-Hexyne C) 3-Hexyne D) 2-Heptyne E) 3-Heptyne Ans: C

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126. Provide the IUPAC name for the alkyne expected to produce the two compounds listed below upon ozonolysis?

CH3CH2CO2H and (CH3)3CCO2H A) 1-tert-butyl-1-butyne B) 2,2-dimethyl-3-hexyne C) 3,3-dimethyl-2-hexyne D) 5,5-dimethyl-3-hexyne E) 3-octyne Ans: B

127. Which alkyne would produce the products below upon ozonolysis?

OH O C O O 1. O3 2. H2O ? HO O OH O + ₊ A) HC≡CC≡CCH2C≡CH B) HC≡CCH2CHCH2C≡CH C) CH3C≡CCH2C≡CCH3 D) HC≡CCH2CH2C≡CCH3 E) CH3C≡CC≡CC≡CH Ans: D

Topic: Alkylation of Terminal Alkynes Section: 10.10

128. What is the IUPAC name for the expected product of the transformation below?

1) NaNH2 2) CH₃CH₂CH₂Br H H₃C A) Propyne B) 1-Hexyne C) 2-Hexyne D) 3-Hexyne E) (E)-3-Hexyne Ans: C

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129. What is the IUPAC name for the expected final product of the transformation below? 1) NaNH2 2) CH3CH2CH2CH2Br H H 3) NaNH2 4) CH3CH2Br ? A) 5-Decyne B) 3-Hexyne C) 1-Octyne D) 3-Octyne E) 5-Octyne Ans: D

130. What is the expected major final product of the reaction sequence shown below?

1) NaNH2 C C H H 3) NaNH2 4) CH3Br 2) Br C C ? I II III IV V C C C C C C C C A) I B) II C) III D) IV E) V Ans: B

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1) NaNH2 C C H H 3) NaNH2 4) 2) C C ? I II III IV C C C C C C Br Br A) I B) II C) III D) IV

E) None of the shown products will be produced. Ans: D

132. What is the expected major product of the reaction sequence shown below? HC≡C:– + (CH3)2CHCH2Br → ? A) CH≡CH + (CH3)2CHC≡CH B) (CH3)2CHC≡CCH3 C) (CH3)2CHCH2C≡CH D) (CH3)2CHCHBrC≡CH E) CH3CHCH2C≡CCH3 Ans: C

133. Which of the alkyl bromides listed would work as a reagent in step 2 of the reaction sequence shown, with the resulting major product being an internal alkyne?

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Br Br Br Br Br I II III IV V 1) NaNH2 2) R–Br R A) I and III B) II and IV C) III, IV, V D) I, II, IV E) II, III, V Ans: D

134. Why would the following reaction sequence not produce the expected product shown? 1) NaNH2 C C H H 3) NaNH2 4) CH3Br 2) Br C C (NOT produced)

A) NaNH2 is used in the reduction of alkynes to trans alkenes.

B) The secondary alkylhalide would undergo an elimination reaction. C) Br is not a good enough leaving group.

D) The terminal alkyne is not acidic enough to be deprotonated.

E) The reaction sequence is correct and will produce the shown product. Ans: B

Topic: Synthetic Strategies Section: 10.11

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H H3C 1) NaNH2 2) (CH3)2CHCH2Br 3) Na, NH₃(l) ? I II III IV V A) I B) II C) III D) IV E) V Ans: A

136. Which of the compounds listed would be a final major product for the following reaction sequence? Br 1) 2 NaNH₂ NH3 Br I II III IV V Br 2) HBr ROOR ? Br Br Br Br A) I B) II C) III D) IV E) V Ans: C

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137. Which of the following methods would be expected to efficiently produce cis-2-butene? A) CH3CHBrCH2CH3 + (CH3)3COK/(CH3)3COH B) CH3C≡CCH3 + H2, Pt C) CH3C≡CCH3 + H2, Ni2B (P-2) D) CH3C≡CCH3 + Na, NH3(l) E) CH3CHBrCH2CH3 + NaNH2 Ans: C

138. Which sequence of reagents would be expected to accomplish the transformation shown?

?

A) 1) HBr; 2) 2 NaNH2

B) 1) Br2; 2) 2 NaNH2

C) 1) Br2, H2O; 2) NaNH2

D) 1) HBr/ROOR; 2) excess NaNH2

E) 1) Na, NH3(l)

Ans: B

139. Which sequence of reagents would be expected to accomplish the transformation of 1-butyne shown below?

HC C CH2CH3

?

HO

A) 1) H2O/H2SO4, HgSO4 cat.; 2) H2, Pt

B) 1) HBr; 2) H2, Pt; 3) NaOH

C) 1) H2, Lindlar catalyst; 2) BH3•THF; 3) H2O2, NaOH

D) 1) HBr, peroxides; 2) NaOH; 3) H2, Pt

E) 1) O3 2) H2O

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140. Which sequence of reactions is expected to produce cis-3-octene as the final, and major, organic product?

1) propyne, NaNH₂ 2) 1-bromopentane

3) aqueous H₂SO₄, cat. HgSO₄

1) 1-butyne, NaNH₂ 2) 1-bromobutane 3) H₂, Lindlar's cat. I II III IV V 1) propyne, NaNH₂ 2) 1-bromopentane 3) H₂, Ni₂B (P-2) 1) 1-butyne, NaNH₂ 2) 1-bromobutane 3) Na, NH₃(l) 1) 1-butyne, NaNH₂ 2) 1-bromobutane 3) H₂, Pd/C A) I B) II C) III D) IV E) V Ans: B

141. Which sequence of reactions is expected to produce the product below as the final, and major, organic product?

D OH HO D H H ? _{+ enantiomer}

A) 1) H2, Lindlar’s cat.; 2) OsO4; 3) NaHSO3/H2O

B) 1) H2, Pt; 2) OsO4; 3) NaHSO3/H2O

C) 1) OsO4; 2) NaHSO3/H2O; 3) H2, Lindlar’s cat.

D) 1) Na, NH3(l); 2) OsO4; 3) NaHSO3/H2O

E) 1) OsO4; 2)NaHSO3/H2O; 3) Na, NH3(l)

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CH3 OH HO H H CH3 ? _{+ enantiomer}

A) 1) Na, NH3(l); 2) OsO4; 3) NaHSO3/H2O

B) 1) H2, Lindlar’s cat.; 2) MCPBA; 3) H3O+

C) 1) H2, Ni2B (P-2); 2) KMnO4, NaOH (cold)

D) Both A and B E) Both A and C Ans: D

CH₂CH₃ Br Br H H ? _{+ enantiomer} A) 1) Br2; 2) H2, Lindlar’s cat. B) 1) H2, Lindlar’s cat.; 2) Br2 C) 1) Br2; 2) Na, NH3(l) D) 1) Na, NH3(l); 2) Br2 E) 1) Br2, 2) H2, Pt Ans: B

144. What is the final major product expected for the following reaction sequence?

1) H2, Ni2B (P-2) 2) Cl2

A) (R)-3-Chlorohexane B) (S)-3-Chlorohexane C) meso-3,4-Dichlorohexane

D) Racemic (2R,3R) and (2S,3S)-3,4-dichlorohexane E) 2,3-Dichloro-3-hexene

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Ans: D

145. What is the final major product expected for the following reaction sequence?

1) Na, NH₃(l) 2) Br₂

A) (R)-3-Bromohexane B) (S)-3-Bromohexane C) meso-3,4-Dibromohexane

D) Racemic (2R,3R) and (2S,3S)-3,4-dibromohexane E) 2,3-Dibromo-3-hexene

Ans: C

1) , NaNH₂ 2) (CH₃)₂CHCH₂Br

3) aqueous H₂SO₄, cat. HgSO₄

1) , NaNH₂ 2) (CH₃)₂CHBr 3) Disiamylborane 4) H₂O₂, NaOH I II III IV V 1) (CH₃)₂CHBr, NaNH₂ 2) 3) O₃ 4) H₂O 1) , NaNH₂ 2) (CH₃)₂CHCH₂Br 3) BH₃•THF 4) H₂O₂, NaOH 1) (CH₃)₂CHCH₂Br, NaNH₂ 2) 3) 9-BBN 4) H2O2, NaOH O ? HC CH CH₃C CH CH₃C CH HC CH CH₃C CH A) I B) II C) III D) IV E) V Ans: A

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Topic: Alkyne Nomenclature Section: 10.2

147. Determine the possible number of alkynes with molecular formula C5H8.

A) one B) two C) three D) four E) five Ans: C

148. Provide the systematic IUPAC name for CH3CH(CH3)C(CH3)2C≡CCH(CH3)2.

Ans: 2,5,5,6-Tetramethyl-3-heptyne

149. Provide the systematic IUPAC name for CH3C≡CC(CH3)2CH(CH2CH3)2.

Ans: 5-Ethyl-4,4-dimethyl-2-heptyne

150. Provide the systematic IUPAC name for CH3CHBrC≡C(CH2)3CH3.

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151. Provide the systematic IUPAC name for the following compound:

Ans: 4-sec-butyl-2-octyne

152. Draw the line-bond structure for the compound with the IUPAC name: 2,5,9-Trimethyl-2-decen-7-yne.

Ans:

Topic: Acidity of Terminal Alkynes Section: 10.3

153. Rank the following hydrocarbons in order of decreasing acidity (most acidic to least acidic). I II III A) I > II > III B) I > III > II C) II > III > I D) II > I > III E) III > I > II F) III > II > I

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Ans: F

154. Describe a sequence of reactions by which 2-hexyne can be straightforwardly prepared from acetylene.

Ans: 1) NaNH2

2) CH3Br

3) NaNH2

4) CH3CH2CH2Br

155. Determine the reagent(s) required to prepare trans-2-heptene from 2-heptyne? A) H2, Pt B) Na, NH3(l) C) H2, Ni2B D) NaOEt E) H2SO4, H2O Ans: B

156. Provide the reagent(s) expected to accomplish the transformation shown below:

C C CH2CH3 H3CH2C CH3(CH2)4CH3 ? A) H2, Pt B) Na, NH3(l) C) H2, Ni2B D) NaOEt E) H2SO4, H2O Ans: A

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157. Provide the reagent(s) expected to accomplish the transformation shown below:

C C CH2CH3 C C CH3CH2 CH2CH3 ? H3CH2C H H A) H2, Pt B) Na, NH3(l) C) H2, Ni2B D) NaOEt E) H2SO4, H2O Ans: C

158. Determine which compound will react with sodium in liquid ammonia to form trans-3-hexene. A) cis-3-hexene B) trans-2-hexene C) 3-hexyne D) 2-hexyne E) cis-2-hexene Ans: C

159. Provide the structure(s) of the expected major organic product(s) from the following reaction:

HBr ROOR (CH₃)₂CHCH₂C CH

Ans: Br and Br

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Section: 10.7

160. Provide the structure(s) of the expected major organic product from the following reaction:

CH₃CH₂C(CH₃)₂C CH 1) Disiamylborane 2) H2O2, NaOH

Ans: O

161. Provide the structure(s) of the expected major organic product(s) from the following reaction: 1) O3 2) H2O Ans: O OH and O HO

162. Provide the structure(s) of the expected major organic product from the following reaction sequence: Br 1) NaNH2 2) 3) H2 Lindlar's cat. Ans:

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163. Which of the following best explains why the synthetic route shown below would be unsuccessful? 1) CH3CH2Br 2) NaNH2 3) (CH3)3CBr HC C _CH₃_CH₂_{C CC(CH}₃₎₃

A) The alkynide anion is not a strong enough nucleophile to react with 1-bromopropane in step 1.

B) Sodium amide is not a strong enough base to deprotonate the terminal alkyne in step 2.

C) The alkynide anion formed by reaction with sodium amide will facilitate an E2 (rather than SN2) reaction with t-butyl bromide.

D) Both substitution reactions will occur on the same end of the alkyne, making a product different than the one shown.

E) Reaction with sodium amide will result in formation of a primary alkyne. Ans: C