chapter 10 multiple choice questions

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 CCH3 CH2CH3

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

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Easy 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

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Easy 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

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Easy 4. What is the hybridization of the carbon atoms numbered 1 and 2 respectively in the

following structure?

CCCCH

H

H 1 2

A) sp3, sp2

B) sp2, sp2 C) sp, sp D) sp2, sp E) sp, sp2 Ans: D

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Easy 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

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Easy 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

Topic: Introduction to Alkynes Section: 10.1 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 Difficulty Level: Easy 8. What is the correct IUPAC name for the molecule shown below?

H2C C C CH2C

BrCH3

CH3H3C

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 CHCH2CH3

CH2CH3CCH3CH2

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy

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

C CHCH2CH2CH3

CH2CH3CHCH3C

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


CC

H3CCH3

CH3HCCH3C

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

Topic: Nomenclature of Alkynes Section: 10.2

Difficulty Level: Easy 13. What is the correct IUPAC name for the molecule shown below?

ClCl

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

Topic: Nomenclature of Alkynes Section: 10.2

Difficulty Level: Easy 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 20. Provide the systematic IUPAC name for HC≡CCH2CH2CH3.

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 22. Provide the systematic IUPAC name for Cl3C(CH2)4C≡CH.

A) 4,4,4-Trichloro-1-butyne

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 25. What is the correct IUPAC name for the molecule shown below?

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

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 26. Which of the following is an acceptable structure for (R)-5-bromohept-2-yne.

I II III IV V

BrBr

BrBr 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

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 29. Which structure shown below represents (Z)-3,5-dichloro-3-hexen-1-yne?

ClI II III IV

Cl

ClClCl

Cl

Cl

Cl

A) I B) II C) III D) IV E) I and II are both correct Ans: B

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 30. Which of the following is an acceptable structure for (2E,4E)-octa-2,4-dien-6-yne?


Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 31. Which of the following is an acceptable structure for octa-3,6-dien-1-yne?

A) HC≡CCH=CHCH=CHCH2CH3 B) CH3CH=CHCH2C≡CC≡CH

C) CH3CH=CHCH2CH=CHC≡CH D) CH3C≡CCH=CHCH=CHCH3 E) H2C=CHC≡CCH2CH=CHCH3 Ans: C

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Hard 33. What is the correct IUPAC name for the molecule shown below?

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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Hard 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

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Hard 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 Difficulty Level: Easy 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: 37. Rank the following bases, with the strongest base first, then by decreasing basicity.

HC C CH3CH2O H2NCH3CH2 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

Topic: Acidity of Acetylene and Terminal Alkynes

Section: 10.3 Difficulty Level: Easy 38. Rank the following acids, with the strongest acid first, then by decreasing acidity.

I II III IV V

H2O CH3CH3 NH3H2C HC CHCH2

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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Easy 39. Which of the circled hydrogen atoms is the most acidic?

I II III IV V

H3C C C HH2C CH

HC HH

CH3H3C C H

CH3

CH3H3CC H

H

HH


Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Easy 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Easy

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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Easy 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Moderate 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Moderate 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. C) Methanol is a poor solvent for dissolving alkynes.

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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Moderate 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Moderate 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Hard 47. Which of the circled hydrogen atoms is the least acidic?

I II III IV V

H3C C C HH2C CH

HC HH

CH3H3C C H

CH3

CH3H3CC H

H

HH

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

Ans: C Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Hard 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 Difficulty Level: Easy 49. For the transformation shown below, select the expected major product.

Br

Br

xs NaNH2

NH3

I II III IV V

HC C CH2

NH2

H2N

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

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Easy 50. For the reaction shown below, select the expected major product.

BrBr KOH

Δ?

BrBrO

Br

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

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Moderate 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

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Hard 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

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Hard 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 Difficulty Level: Easy 54. For the reaction shown, select the expected major organic product.

I II III IV V

?H2Pt

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


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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 58. Select the reagent(s) expected to accomplish the transformation shown below.

C CCH3CH2 CH2CH3? CH3CH2CH2CH2CH3

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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 62. Select the reagent(s) expected to accomplish the transformation shown below.

CCH3CH2C

CH2CH3C CCH3CH2 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 68. Select the reagent(s) expected to accomplish the transformation shown below.

C CCH2CH3H3CH2C

C CCH3CH2 CH2CH3? H H

A) H2, Ni B) H2, Ni2B C) H2, Lindlar’s catalyst D) A and B E) B and C Ans: E

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 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


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


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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 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

Topic: Reduction of Alkynes Section: 10.5 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 74. For the reaction shown below, the resulting stereochemistry of the expected

product is best described as: H2Pt

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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Hard 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 Difficulty Level: Easy 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 ClCl

I II III IV V

Cl

Cl

Cl


Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 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

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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 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


Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 82. What is the major expected product(s) of the reaction shown below?

C CCH3CH2 CH3HCl

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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 83. For the reaction shown, select the expected major organic product.

1) 1 eq HCl

2) 1 eq HBr?

I II III IV V

BrCl

ClBr

BrCl Br

Cl

Br

Cl

Cl

Br


Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 84. Which of the compounds shown below would be the most likely product expected

from the reaction scheme shown? HBr

ROOR?(CH3)2CHCH2C CH

Br

Br

Br

BrBr 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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 87. For the transformation shown, select the most appropriate reagent(s) to effect the

change. ?

(CH3)2CHCH2CCH3O

(CH3)2CHCH2C CH

A) H2SO4, HgSO4 B) 1. Disiamylborane, 2. HO–, H2O, H2O2 C) K2Cr2O7, H+ D) NaOCl E) H2, Pd Ans: A

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 88. For the transformation shown, select the most appropriate reagent(s) to effect the

change. ?

(CH3)2CHCH2CH2CH(CH3)2CHCH2C CHO

A) H2SO4, HgSO4 B) 1. Disiamylborane, 2. HO–, H2O, H2O2 C) K2Cr2O7, H+ D) NaOCl E) H2, Pd Ans: B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 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

OOOH

O OH


Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 90. For the reaction shown, which of the compounds listed would be the expected


H2O, H2SO4HgSO4

?

I II III IV V

O

O

O

OH

OH



major organic product?

H2O, H2SO4HgSO4

OH OH

OH

O O

O

HO OH

I II III IV V

?




?

I II III IV V

O

O

O

OH

OH

1) BH3•THF

2) H2O2, NaOH




OH

I II III IV V

?

OOH OOH

OH

1) BH3•THF

2) H2O2, NaOH

A) I

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



?

I II III IV V

1) Disiamylborane

2) H2O2, NaOH

OO

OH

OH OHOH




CH3CH2C(CH3)2C CH

I II III IV V

OO OHO OH

?1) Disiamylborane

2) H2O2, NaOH

A) I

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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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 OOH OHOH

OH


Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 97. For the reaction shown, which of the compounds below would be the expected enol

intermediate?

OH

I II III IV V

OH OOH OH OH

OH

?1) BH3•THF

2) H2O2, NaOH

A) I

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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 98. Which of the ketones below could not be prepared by an acid-catalyzed hydration

of an alkyne? O OOO O


Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 100. In an acid-catalyzed hydration, which of the following alkynes is expected to

produce a single ketone? A) 2-decyne B) 3-decyne

C) 4-decyne D) 5-decyne E) All of the above will give a single product Ans: D

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 103. Which of the following alkynes would give a single product under hydroboration-

oxidation conditions? A) 1-hexyne B) 2-hexyne C) 3-hexyne D) A and B would each give a single product

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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

OHOHOH


Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 106. For the reaction below, which of the alkynes listed would be expected to produce

the product under the conditions shown?

I II III IV V

1) 9-BBN

2) H2O2, NaOH? O


Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Ans: A Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 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, NaOH1) BH3•THF

2) H2O2, NaOH

H2O, H2SO4HgSO4

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 Difficulty Level: Easy 111. What is the major product of the reaction shown below?

C CCH3CH2CH2 CH3excess 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

Ans: E Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 112. Which of the compounds shown below would be the most likely product expected


xs Cl2 ?

Cl

CH3CH2C CH

Cl Cl ClCl

I II III IV V

Cl

Cl

Cl

Cl

Cl Cl

Cl


Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 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

BrBr

BrH

Br

BrBr

Br

CCl4

H Br

Br BrBr Br


Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 114. Which of the compounds shown below would be the most likely product expected


?(CH3)2CHCH(CH3)C

Br

BrBrBr

I II III IV V

CHexcess Br2

CCl4

BrBr BrBrBr

Br

Br

Br


Topic: Halogenation of Alkynes (Hydrohalogenation…) Section: 10.8 Difficulty Level: Easy 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

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 116. For the reaction below, select the structure of the major organic product.

xs Br2 ?

I II III IV V

Br

Br Br

Br

BrBr

BrBr

Br

BrBr Br

Br


Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Moderate 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 Difficulty Level: Easy 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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy

119. Predict the major organic products of the reaction below.

1) O3

2) H2O

O

OH O

HOC O

OO

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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 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

++ + + +

OC OHH3C

C OOH3C

O

OH HO

O

OH

?

OH O

C OO

H


Topic: Ozonolysis of Alkynes

Section: 10.9 Difficulty Level: Easy 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

HOO C OO 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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 122. What is the expected major product of the reaction sequence shown below?

I II III IV V

1. O3

2. H2O?

O

OCO2HCO2H

CO2HOO

O

O


Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 123. Ozonolysis of one mole of the compound shown is expected to produce how many

moles of CO2 upon completion of the reaction?

A) 1 B) 2 C) 3 D) 4 E) 8 Ans: C

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Moderate 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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Moderate 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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Hard

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

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Hard 127. Which alkyne would produce the products below upon ozonolysis?

OH

OC OO

1. O3

2. H2O? HO

OOH

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 Difficulty Level: Easy 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

Topic: Alkylation of Terminal Alkynes Section: 10.10

Difficulty Level: Easy 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

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 130. What is the expected major final product of the reaction sequence shown below?

1) NaNH2C

CH

H

3) NaNH2

4) CH3Br2)Br

CC

?

I II III IV V

CC C C

C CC C


Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 131. What is the expected major final product of the reaction sequence shown below?

1) NaNH2C

CH

H

3) NaNH2

4)2)

CC

?

I II III IV

CCC C

C C

BrBr

A) I B) II C) III D) IV E) None of the shown products will be produced. Ans: D

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Moderate 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

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Moderate 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?

Br

BrBr

BrBr

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

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Hard 134. Why would the following reaction sequence not produce the expected product

shown?

1) NaNH2C C H

H

3) NaNH2

4) CH3Br2) 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 Difficulty Level: Easy 135. What is the final major product expected for the following reaction sequence?

H

H3C

1) NaNH22) (CH3)2CHCH2Br3) Na, NH3(l)

?

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

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 136. Which of the compounds listed would be a final major product for the following

reaction sequence?

Br 1) 2 NaNH2

NH3Br

I II III IV V

Br

2) HBrROOR

?

Br

BrBr

Br


Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 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

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 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

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate 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 Ans: C

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate 140. Which sequence of reactions is expected to produce cis-3-octene as the final, and

major, organic product?

1) propyne, NaNH22) 1-bromopentane3) aqueous H2SO4, cat. HgSO4

1) 1-butyne, NaNH22) 1-bromobutane3) H2, Lindlar's cat.

I II III

IV V

1) propyne, NaNH22) 1-bromopentane3) H2, Ni2B (P-2)

1) 1-butyne, NaNH22) 1-bromobutane3) Na, NH3(l)

1) 1-butyne, NaNH22) 1-bromobutane3) H2, Pd/C


Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 141. Which sequence of reactions is expected to produce the product below as the final,

and major, organic product?

D OHHO

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) Ans: A



CH3OH

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



CH2CH3Br

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

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 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

Ans: D Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 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) , NaNH22) (CH3)2CHCH2Br3) aqueous H2SO4, cat. HgSO4

1) , NaNH22) (CH3)2CHBr3) Disiamylborane4) H2O2, NaOH

I II III

IV V

1) (CH3)2CHBr, NaNH22) 3) O34) H2O

1) , NaNH22) (CH3)2CHCH2Br3) BH3•THF4) H2O2, NaOH

1) (CH3)2CHCH2Br, NaNH22)3) 9-BBN4) H2O2, NaOH

O?

HC CH CH3C CH

CH3C CHHC CH

CH3C CH


Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 147. Determine the possible number of alkynes with molecular formula C5H8.

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

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 148. Provide the systematic IUPAC name for CH3CH(CH3)C(CH3)2C≡CCH(CH3)2. Ans: 2,5,5,6-Tetramethyl-3-heptyne Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 149. Provide the systematic IUPAC name for CH3C≡CC(CH3)2CH(CH2CH3)2.

Ans: 5-Ethyl-4,4-dimethyl-2-heptyne Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 150. Provide the systematic IUPAC name for CH3CHBrC≡C(CH2)3CH3.

Ans: 2-Bromo-3-octyne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 151. Provide the systematic IUPAC name for the following compound:

Ans: 4-sec-butyl-2-octyne Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 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 Difficulty Level: Easy 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

Ans: F Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Easy 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

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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 Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 156. Provide the reagent(s) expected to accomplish the transformation shown below:

C C CH2CH3H3CH2C CH3(CH2)4CH3?


Ans: A

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 157. Provide the reagent(s) expected to accomplish the transformation shown below:

C CCH2CH3

C CCH3CH2 CH2CH3?

H3CH2C

HH


Ans: C Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 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

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 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 Topic: Hydration of Alkynes

Section: 10.7 Difficulty Level: Easy 160. Provide the structure(s) of the expected major organic product from the following

reaction:

CH3CH2C(CH3)2C CH1) Disiamylborane

2) H2O2, NaOH

Ans: O Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 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

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 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: Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate

163. Which of the following best explains why the synthetic route shown below would be unsuccessful?

1) CH3CH2Br2) NaNH2

3) (CH3)3CBr

HC C CH3CH2C CC(CH3)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

chapter 10 multiple choice questions

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