ch10-testbank

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 C3 sigma bond?

A) sp – sp sp 2 B) sp – sp sp2 C) sp3 – sp sp3 D) p – p E) sp3 – sp sp Ans: A


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

A) sp – sp sp 2 B) sp – sp sp2 C) sp3 – sp sp3 D) p – p E) sp3 – sp sp Ans: A


The sigma bond of an alkyne is formed from the overlap of which orbitals? A) B) C)

sp3 – sp sp3 p – p sp2 – sp sp2

D) E) Ans:

s – s sp – sp sp E


What is the hybridization of the carbon atoms numbered 1 and 2 respectively in the following structure?

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

sp3, sp2 sp2, sp2 sp, sp sp2, sp sp, sp2 D


The C≡C bond of an alkyne is composed of which bond types? A) B) C) D) E) Ans:

three anti-bonds three σ bonds two σ bonds and one π bond one σ bond and two π bonds three π bonds D


Which of the following statements best describes the general reactivity of alkynes? A) B)

An alkyne reacts as a nucleophile and is therefore electron rich. An alkyne reacts as a nucleophile and is therefore electron poor.

C) D) E) Ans:

Alkynes fail to undergo electrophilic addition reactions, unlike alkenes. An alkyne reacts as an electrophile and is therefore electron rich. An alkyne reacts as an electrophile and is therefore electron poor. A

Topic: Introduction to Alkynes Section: 10.1 Difficulty Level: Moderate 7.

Which of the following statements is true about propyne, H –C≡C– CH CH3? A) B) C) D) E) Ans:

It contains a total of three sigma bonds. It contains a total of three pi bonds. The H –C≡C bond angle is about about 109.5°. The C≡C– C bond angle is 180°. All carbon-carbon bonds are of equal length. D

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Easy 8.

What is the IUPAC name for the molecule shown below?

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

6-bromo-3-octyne 6-bromo-6-methyl-3-heptyne 2-bromo-2-methyl-4-heptyne 6-bromo-6,6-dimethyl-3-hexyne 2-bromo-4-octyne B



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

1,1-diethyl-2-pentyne 3-(1-butynyl)pentane 5-ethyl-3-octyne 3-ethyl-4-heptyne 5-ethyl-3-heptyne E



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

2-methyl-5-propyl-3-heptyne 5-ethyl-2-methyl-3-octyne 1-isopropyl-3-ethyl-1-hexyne 6-methyl-3-propyl-4-heptyne 4-ethyl-7-methyl-5-octyne B


What is the IUPAC name for the molecule shown below? below?

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

2,2,3-trimethyl-4-hexyne 4-tert -butyl-2-pentyne -butyl-2-pentyne 4,5,5-trimethyl-2-hexyne 4,5,5,5-tetramethyl-2-pentyne 2,2-dimethyl-3-(1-propynyl)butane C



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

5,6,6-trimethyl-1-heptyne 5-tert -butyl-1-hexyne -butyl-1-hexyne 2,2,3-trimethyl-6-heptyne 2,2,3-(3-butynyl)butane sec-butyl-tert -butylacetylene -butylacetylene A



A) B) C) D) E) Ans

1,1,1-trichloro-4-hexyne 4,4,4-trichloro-1-butyne 1,1,1-trichloro-2-butyne 5,5,5-trichloro-2-pentyne 6,6,6-trichloro-2-hexyne E



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

4,4-dimethyl-2-pentyne 2,2-dimethyl-4-heptyne 1-tert- butyl-3-heptyne butyl-3-heptyne 6,6-dimethyl-3-heptyne 6,6,6-trimethyl-3-hexyne D

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

15.


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

4-ethyl-2-pentyne 2-ethyl-3-pentyne 3-methyl-4-hexyne 4-methyl-2-hexyne sec-Butylpropyne D


Which of the following is a structure for hepta-3,6-dien-1-yne?

I

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

II II

III

I II III IV V A


Which of the following is the structure for 2-hexyne?

A) B) C) D)

I II III IV

IV

V

Ans:

C


Which of the following is the structure for 3-sec-butyl-1-heptyne?

I

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

II II

III

I II III IV V B


Provide the IUPAC name for BrCH2CH2C≡CCH2CH3. A) B) C) D) E) Ans:

1-bromo-3-hexyne 6-bromo-3-hexyne 1-bromo-2-hexyne 6-bromo-4-hexyne 1-bromo-4-hexyne A


Provide the IUPAC name for HC≡CCH2CH2CH3. A) B) C) D)

pentyne 1-pentyne butyne 1-butyne

IV

V

E) Ans:

2-butyne B


Provide the IUPAC name for Cl3CCH2CH2CH2C≡CH. A) B) C) D) E) Ans:

6,6,6-trichloro-1-hexyne 1,1,1-trichloro-5-hexyne 5,5,5-trichloro-1-pentyne 1-heptyne trichlorobutylacetylene A

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Moderate 22.

Provide the IUPAC name for Cl3C(CH2)4C≡CH. A) B) C) D) E) Ans:

4,4,4-trichloro-1-butyne 1,1,1-trichloro-6-heptyne 1,1,1-trichloro-5-heptyne 6,6,6-trichloro-1-hexyne 7,7,7-trichloro-1-heptyne E


Provide the IUPAC name for (CH3)2CHC≡ CHC≡CCH2C(CH3)3. A) B) C) D) E) Ans:

1,1,5,5,5-pentamethyl-2-pentyne 1,1,1,5,5-pentamethyl-3-pentyne 2,2,6-trimethyl-4-heptyne 2,6,6-trimethyl-3-heptyne tert -butylisopropylacetylene -butylisopropylacetylene D


Provide the systematic IUPAC name for the molecule below: (CH3)3CCH2C≡CCH2CH(CH3)CH2CH3 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



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

3-bromo-4-acetylenylheptane 3-(1-bromopropyl)-1-hexyne 3-bromo-4-propyl-5-hexyne 4-bromo-3-propyl-1-hexyne 4-ethynyl-5-bromo-heptane D


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

A) B) C) D)

I II III IV

E) Ans:

V E



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

(E)-5-methyl-5-hepten-1-yne (Z)-5-methyl-5-hepten-1-yne (E)-3-methyl-2-hepten-6-yne (Z)-3-methyl-2-hepten-6-yne (E)-2-butynyl-2-butene A



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

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


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

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

I II III IV I and II are both correct B


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

I

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

II II

III

IV

I II III IV V D


Which of the following is a structure for octa-3,6-dien-1-yne? A) B) C) D) E) Ans:

HC≡CCH=CHCH=CHCH2CH3 CH3CH=CHCH2C≡CC≡CH CH3CH=CHCH2CH=CHC≡CH CH3C≡CCH=CHCH=CHCH3 H2C=CHC≡CCH2CH=CHCH3 C

Topic: Nomenclature of Alkynes

V

Section: 10.2 Difficulty Level: Moderate 32.

Which of the following is the structure for 2,5,5-trimethylhept-3-yne? A) B) C) D) E) Ans:

CH3CH2CH(CH3)C≡CCH2CH(CH3)2 CH3CH2C(CH3)2C≡CCH(CH3)2 (CH3CH2)2C(CH3)C≡CCH2CH3 CH3CH2C(CH3)2C≡CC(CH3)3 CH3CH2CH2CH(CH3)C≡CC(CH )C≡CC(CH3)3 B

Topic: Nomenclature of Alkynes Section: 10.2 Difficulty Level: Hard 33.


A) B) C) D) Ans:

(4 R,5 Z )-4-chlorohept-5-en-2-yne )-4-chlorohept-5-en-2-yne (4S,5 E )-4-chlorohept-5-en-2-yne )-4-chlorohept-5-en-2-yne (2 E ,4 ,4S )-4-chlorohept-2-en-5-yne )-4-chlorohept-2-en-5-yne (2 E,4 R)-4-chlorohept-2-en-5-yne D


What is the IUPAC name for diisobutylacetylene? A) B) C) D) E) Ans:

diisopropylbutyne 2,7-dimethyl-4-octyne 3,6-dimethyl-4-octyne 2,5-diethyl-3-hexyne 2,2,5,5-tetramethyl-3-hexyne B


What is the IUPAC name for di-sec- butylacetylene? butylacetylene? A) B) C) D) E) Ans:

2-ethyl-5-methyl-3-heptyne 2,7-dimethyl-4-octyne 3,6-dimethyl-4-octyne 2,5-diethyl-3-hexyne 2,2,5,5-tetramethyl-3-hexyne C

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Easy 36.

Rank the following carbanions in order of increasing base strength.

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

I < II < III II < III < I III < II < I III < I < II II < I < III A

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: 37.

Rank the following bases in order of decreasing basicity.

A) B) C) D) E)

III > I > V > II > IV III > V > IV > I> II V > I > III > II > IV III > IV > II > V > I IV > II > I > III > V

Ans:

B


Rank the following acids in order of decreasing acidity.

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

V > I > IV > II > III III > IV > II > I > V V > I > III > II > IV I > IV > V > II > III IV > I > V > II > III D


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

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

I II III IV V E


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

Brønsted acid. Brønsted base.

C) D) E) Ans:

reducing agent. catalyst. electrophile. B


Which of the bases below would quantitatively deprotonate a terminal alkyne? A) B) C) D) E) Ans:

BuLi NH3 NaOH NaOCH2CH3 t -BuOK -BuOK A


Which of the bases bases below would result result in the most complete deprotonation deprotonation of the alkyne, shown in the reaction below?

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

NaOCH2CH3 (sodium ethoxide) t -BuONa -BuONa (sodium tert -butoxide) -butoxide) NaH (sodium hydride) NaHCO3 (sodium bicarbonate) NaOH (sodium hydroxide) C

Topic: Acidity of Acetylene and Terminal Alkynes Section: 10.3 Difficulty Level: Moderate 43.

Which statement below best explains why the K a of acetylene is greater than that of ethylene? A) B)

Acetylide anions are resonance stabilized. The 4  electrons of the acetylide anion better stabilize a negative charge.

C) D) E) Ans:

The electronegativity of sp carbons is greater than than that of sp2 carbons. The electronegativity of sp carbons is less than that of sp2 carbons. Acetylene has only two hydrogen atoms while ethylene has four. C


Select the best explanation for why methanol, CH3OH, cannot be be used as a solvent for the deprotonation of a terminal alkyne by sodium amide, NaNH2. A) B) C) D) E) Ans:

Sodium amide is not a strong enough base to deprotonate the alkyne. Sodium amide in methanol reduces alkynes to alkenes. Methanol is a poor solvent for dissolving alkynes. Methanol is more acidic than the alkyne and will be deprotonated instead. Methanol is toxic, and should be avoided when possible. D


What are the products of the reaction shown below? CH3OH + CH3C≡C – Na+ → ? A) B) C) D) E) Ans:

CH3C≡CCH3 + Na+OH – CH3C≡CH + CH3O – Na+ CH3C≡COCH3 + Na+OH – CH3OC≡CH + Na+CH3 – no reaction B


The major result of treating 1-butyne with with 6M aqueous aqueous NaOH would be: A) B) C)

the production of the sodium alkynide. the production of an alkene. the production of an alkane.

D) E) Ans:

the production of an enol. nothing, as the alkyne would not react to an appreciable extent. 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? acidic?

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

I II III IV V C


Of the species listed below, select those less basic than acetylide. A) B) C) D) E) Ans:

BuLi NaNH2 NaOCH3 both A and C both B and C C

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Easy 49.

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

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

I II III IV V D

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Moderate 50.

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

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

3-methylhexane 1-bromo-3-methylhexene 2-bromo-3-methylhexene 3-methyl-1-hexyne 3-methyl-2-hexyne D


When preparing terminal alkynes by an elimination reaction, sodium amide (NaNH2) dissolved in liquid ammonia (NH3) is used used most frequently. 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) C) D) E) Ans:

Sodium amide deprotonates the terminal alkyne, driving formation of the alkynide ion. Only sodium amide is a strong enough base to deprotonate a carbon. Terminal alkynes are more stable than the internal alkynes, and are always the favored product. Steric hindrance favors preparation of the less substituted terminal alkyne. B

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 52.

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

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

I II III IV V C



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

I II III IV V B



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

I II III IV V A


Complete reduction of 1 mole of (3 E ,5 ,5 Z )-3-methylhepta-3,5-dien-1-yne )-3-methylhepta-3,5-dien-1-yne will require how many moles of hydrogen (H2)? A) B) C) D) E) Ans:

1 2 3 4 5 D


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

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

H2, Ni H2, Ni2B Na, NH3(l) A or B B or C A


Select the best reagent expected to convert 3-heptyne to cis-3-heptene. cis-3-heptene. A) B) C) D) E) Ans:

NaNH2, NH3 Na, NH3 H2, Lindlar’s catalyst Both A and C Both B and C C


Which of the reagents below would convert 2-pentyne to trans-2-pentene? A) B) C) D) E) Ans:

NaNH2, NH3 Na, NH3 H2, Lindlar’s catalyst H2, Pd/C H2O, HgSO4/H2SO4 B


Select the best reagent to convert 3-heptyne to trans-3-heptene? trans-3-heptene? A) B) C) D) E) Ans:

Na/NH3 1 eq. NaNH2, NH3 xs NaNH2, NH3 H2/Pt H2/Lindlar's catalyst A



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

H2, Pd H2, Lindlar’s catalyst Na, NH3(l) A or B B or C C


Reaction of 3,4,5-trimethyl-4-hexen-1-yne with H2 and Pd/C will produce which of the following compounds? A) B) C) D) E) Ans:

2,3,4-trimethylhexane 3,4,5-trimethylhexane 2,3,4-trimethyl-1-hexene 3,4,5-trimethyl-1-hexyne 2,3,4-trimethyl-5-hexyne A

2


Reaction of (3 E ,5 ,5 Z )-3-methylhepta-3,5-dien-1-yne )-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-butylbutane C) 3-methylheptane D) 3-methyl-1-heptyne E) (3 E ,5 ,5 Z )-3-methyl-1,3,5-heptatriene )-3-methyl-1,3,5-heptatriene Ans: C 2


Of the reaction conditions provided below, which would be expected to convert 1 mole of 4-methyl-1-pentyne into 2-methylpentane? A) B) C) D) E) Ans:

H2, Lindlar’s catalyst Na, NH3(l) 2 moles of HCl 2 moles H2, Pt 1 mole H2, Pt D


Which reagents shown below would be expected to convert 2-pentyne to to (Z)-2 pentene? A) B) C) D) E) Ans:

H2, Pt Na, NH3 H2, Lindlar's catalyst excess HCl HgSO4, H2O C

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Moderate 65.

For the the reaction shown below, below, what is the IUPAC name of the expected product?

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

2-methylhexane ( Z Z )-2-methyl-4-hexene )-2-methyl-4-hexene ( E E )-2-methyl-4-hexene )-2-methyl-4-hexene ( Z Z )-5-methyl-2-hexene )-5-methyl-2-hexene ( E E )-5-methyl-2-hexene )-5-methyl-2-hexene E



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

H2, Ni H2, Ni2B H2, Lindlar’s catalyst A and B B and C E


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) B) C) D) E)

(E)-4-methyl-2-pentene (Z)-4-methyl-2-pentene 2-methylpentane 4-methylpentane Equal mixture of A and B

Ans:

C


What is the expected major organic product from treatment of 4-methyl-2-pentyne with hydrogen in the presence of Lindlar's catalyst? A) B) C) D) E) Ans:

(E)-4-methyl-2-pentene (Z)-4-methyl-2-pentene (E)-2-methyl-2-pentene (Z)-2-methyl-2-pentene 2-methylpentane B


What is the expected major organic product from treatment of 4-methyl-2-pentyne with sodium metal in liquid ammonia? A) B) C) D) E) Ans:

(E)-4-methyl-2-pentene (Z)-4-methyl-2-pentene (E)-2-methyl-2-pentene (Z)-2-methyl-2-pentene 2-methylpentane A


In the reaction between an alkyne and Na metal in liquid ammonia, the role of Na is: A) B) C) D) E) Ans:

Brønsted acid. Brønsted base. reducing agent. catalyst. electrophile. C

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Modertate 71.

In a dissolving metal reduction of an alk yne, a postulated intermediate is the trans alkenyl radical, shown below. In which orbital type would the unpaired electron be located?

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


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

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

only (S ) only ( R R) racemic meso achiral E


Complete hydrogenation of a mixture of 1-octyne, 2-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) C) D) E) Ans:

2 3 6 8 A

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Hard 74.

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

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

( R,E R,E ) (S,E ) ( R,Z R,Z ) (S,Z ) only (S ) D

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 75.

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

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

I II III IV V C


The expected major product from from the treatment of 1-pentyne with with 1 equivalent of HBr is: A) B) C) D) E) Ans:

1-bromo-1-pentene 2-bromo-1-pentene 1,1-dibromopentane 2,2-dibromopentane 1,2-dibromopentane B


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

1-bromo-1-pentene 2-bromo-1-pentene 1,1-dibromopentane 2,2-dibromopentane 1,2-dibromopentane D


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

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

I II III IV V C

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 79.

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

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

2,2-Dichloropentane 3,3-Dichloropentane 2,3-Dichloropentane A and B B and C D



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

I II III IV V D


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

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

I and II III and IV II and III II and IV I and IV E


Select the expected major product(s) from the treatment of 1-pentyne with 1 equivalent of HBr in the presence of peroxides. A) B) C) D) E) Ans:

2-bromo-1-pentene ( E E )-1-bromo-1-pentene )-1-bromo-1-pentene ( Z Z )-1-bromo-1-pentene )-1-bromo-1-pentene A and B B and C E


What mechanistic mechanistic intermediate 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 an intermediate with partial positive charge on a primary carbon

B) C) D) E) Ans:

Formation of an intermediate with partial positive charge on a secondary carbon Addition of the H atom to the carbon already with an H. Addition of H, from HBr, to the least hindered carbon. Steric hindrance for the approach of the Br atom to the primary carbon. B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 84.

For the transformation shown, select select the most appropriate reagent(s) to effect effect the the change.

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

H2SO4, HgSO4, H2O 1. Disiamylborane, 2. HO – , H2O2 K 2Cr 2O7, H+ NaOCl H2, Pd A


For the transformation shown, select select the most appropriate reagent(s) to effect effect the the change.

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

H2SO4, HgSO4, H2O 1. Disiamylborane, 2. HO – , H2O2 K 2Cr 2O7, H+ NaOCl H2, Pd B


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

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

I II III IV V B


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

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

I II III IV V B

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

88.

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

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

I II III IV V C



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

I II III IV V C

Topic: Hydration of Alkynes

Section: 10.7 Difficulty Level: Easy 90.


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

I II III IV V C



A) B) C) D) E)

I II III IV V

Ans:

E



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

I II III IV V C

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 93.

For the reaction shown, which of the compounds listed would be the expected enol intermediate?

A)

I

B) C) D) E) Ans:

II III IV V A


For the reaction shown, which of the compounds below would be the expected enol intermediate?

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

I II III IV V B


Which of the ketones below could not be be prepared by an acid-catalyzed hydration of an alkyne?

A) B)

I II

C) D) E) Ans:

III IV V D


Consider the the list list of alkyne addition addition reactions below, and select all those that involve an enol intermediate. A) B) C) D) E) Ans:

Hydroboration/oxidation HgSO4 catalyzed hydration in dilute H2SO4 Hydrohalogenation Both A and B Both A and C D


In an acid-catalyzed hydration, which of the following alkynes is expected to produce a single ketone? A) B) C) D) E) Ans:

2-decyne 3-decyne 4-decyne 5-decyne All of the above will give a single product D


In an acid-catalyzed hydration, which of the following alkynes gives gives a single ketone? A) B) C) D)

2-pentyne 2-hexyne 2-heptyne 3-hexyne

E) Ans:

3-heptyne D


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

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

one two three four five B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 100. Which of the following alkynes would give give a single single product under hydroborationoxidation conditions? A) B) C) D) E) Ans:

1-hexyne 2-hexyne 3-hexyne A and B would each give a single product A and C would each give a single product E

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 101. Which of the alkynes below, after undergoing an acid-catalyzed hydration, would be expected to produce two different ketones ketones in nearly equivalent yields? A) B)

1-hexyne 2-hexyne

C) D) E) Ans:

3-hexyne 3-methyl-1-pentyne 4-methyl-1-pentyne B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 102. For the reaction shown, which of the compounds listed below would be the expected major, and final, organic product?

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

I II III IV V D

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 103. For the reaction below, which of the alkynes listed listed would be expected to to produce the product under the conditions shown?

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

I II III IV V C

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 104. What functional group group would be expected to be found in the 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) B) C) D) E) Ans:

aldehyde ketone diol ether carboxylic acid B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 105. What functional group group would be expected to be found in the major, and final, final, organic product upon completion of the reaction below?

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

aldehyde ketone diol enol alkene A

Topic: Hydration of Alkynes Section: 10.7

Difficulty Level: Moderate 106. What is the expected functional functional group produced when cyclooctyne is reacted with disiamylborane, followed with treatment of basic hydrogen peroxide? A) B) C) D) E) Ans:

aldehyde ketone diol ether carboxylic acid B

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Moderate 107. Which of the reagents below, upon completion completion of reaction with a terminal alkyne, would be expected to produce a ketone as the final major organic product?

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

I and II II III and IV I, II and IV I, III and IV B

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 108. What is the major product of the reaction shown below?

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

( E E )-2,3-Dichloro-2-hexene )-2,3-Dichloro-2-hexene ( Z Z )-2,3-Dichloro-2-hexene )-2,3-Dichloro-2-hexene 2,2-Dichlorohexane 3,3-Dichlorohexane 2,2,3,3-Tetrachlorohexane E

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 109. Which of the compounds shown below would be the most likely product expected from the reaction scheme shown?

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

I II III IV V E

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 110. Careful addition addition of 1 equivalent of Br 2 to the alkyne shown below would be expected to produce which of the following as the major organic product?

A) B) C)

I II III

D) E) Ans:

IV V B

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Easy 111. Which of the compounds shown below would be the most likely product expected from the reaction scheme shown?

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

I II III IV V A

Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Easy 112. The expected major product from treatment treatment of 1-pentyne with excess HBr is: is: A) B) C) D) E) Ans:

1,1-dibromo-1-pentene 1,2-dibromo-1-pentene 1,1-dibromopentane 2,2-dibromopentane 1,1,2,2-tetrabromopentane D

Topic: Halogenation of Alkynes Section: 10.8

Difficulty Level: Easy 113. For the reaction below, select the structure of the major organic product.

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

I II III IV V D

Topic: Halogenation of Alkynes Section: 10.8 Difficulty Level: Moderate 114. Select the expected major product(s) product(s) from the treatment of 1-pentyne with 1 equivalent of Br 2. A) B) C) D) E) Ans:

1,1-dibromo-1-pentene ( E E )-1,2-dibromo-1-pentene )-1,2-dibromo-1-pentene ( Z Z )-1-bromo-1-pentene )-1-bromo-1-pentene A and B B and C B

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 115. Which of the following following conditions effectively cleaves all three bonds of a carboncarbon triple bond? A) B) C) D)

HgSO4 and aqueous H2SO4 1) Disiamylborane 2) H2O2, NaOH H2, Lindlar’s catalyst 1) O3 2) H2O

E) Ans:

Na, NH3(l) D

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 116. Predict the major organic organic products of the reaction below.

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

I and II II an III I and IV II and III 1 and III C

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 117. For the reaction sequence shown, what are the expected major organic organic products?

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

I II III IV V B

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 118. What are the expected major products products of the reaction sequence shown below?

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

I and II I, III, and V II, III, and IV I and IV II, III, IV D

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 119. What is the expected major product product of the reaction sequence shown below?

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

I II III IV V B

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 120. Ozonolysis of one mole of the compound shown is is expected to produce how many moles of CO2 upon completion of the reaction?

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

1 2 3 4 8 C

Topic: Ozonolysis of Alkynes

Section: 10.9 Difficulty Level: Moderate 121. Select the alkyne listed below that, that, upon treatment with with ozone followed by water, would not produce carbon dioxide and a carboxylic acid as the final products? A) B) C) D) E) Ans:

Ethyne Propyne 1-Butyne 1-Pentyne 1-Hexyne A

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Moderate 122. Which of the following alkynes, upon ozonolysis, ozonolysis, would be expected to produce only one major organic product? A) B) C) D) E) Ans:

1-Hexyne 2-Hexyne 3-Hexyne 2-Heptyne 3-Heptyne C

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Hard 123. Provide the IUPAC IUPAC name for the alkyne expected to produce the two compounds listed below upon ozonolysis. CH3CH2CO2H and (CH3)3CCO2H A) B) C) D) E) Ans:

1-tert -butyl-1-butyne -butyl-1-butyne 2,2-dimethyl-3-hexyne 3,3-dimethyl-2-hexyne 5,5-dimethyl-3-hexyne 3-octyne B

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Hard 124. Which alkyne would produce the products below upon ozonolysis?

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

HC≡CC≡CCH2C≡CH HC≡CCH2CH2CH2C≡CH CH3C≡CCH2C≡CCH3 HC≡CCH2CH2C≡CCH3 CH3C≡CC≡CC≡CH D

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 125. What is the IUPAC name for for the expected product of the transformation transformation below?

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

Propyne 1-Hexyne 2-Hexyne 3-Hexyne ( E E )-3-Hexyne )-3-Hexyne C

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 126. What is the IUPAC name for for the expected final product of the transformation below?

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

5-Decyne 3-Hexyne 1-Octyne 3-Octyne 5-Octyne D

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 127. What is the expected major final final product of the reaction sequence shown below?

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

I II III IV V B

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Easy 128. What is the expected major final final product of the reaction sequence shown below?

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

I II III IV None of the shown products will be produced. D

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Moderate 129. What is the expected major product product of the reaction sequence shown below? HC≡C HC≡C: – + (CH3)2CHCH2Br  ? A) B) C) D) E) Ans:

CH≡ CH≡CH + (CH3)2CHC≡CH (CH3)2CHC≡ CHC≡CCH3 (CH3)2CHCH2C≡CH (CH3)2CHCHBrC≡ CHCHBrC≡CH CH3CHCH2C≡CCH3 C

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Moderate 130. Which of the alkyl bromides bromides listed would work as a reagent in step 2 of the reaction sequence shown, with the resulting major product being an internal alkyne?

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

I and III II and IV III, IV, V I, II, IV II, III, V D

Topic: Alkylation of Terminal Alkynes Section: 10.10 Difficulty Level: Hard 131. Why would the following reaction sequence not produce the expected product shown?

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

NaNH2 is used in the reduction of alkynes to trans alkenes. The secondary alkyl halide would undergo an elimination reaction. Br is not a good enough leaving group. The terminal alkyne is not acidic enough to be deprotonated. The reaction sequence is correct and will produce the shown product. B

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 132. What is the final major product product expected for the following reaction sequence?

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

I II III IV V A

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 133. Which of the compounds listed would be one of the final major products products for the following reaction sequence?

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

I II III IV V C

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 134. Which of the following methods would be expected to efficiently produce produce cis-2 butene as the major organic product? A) B) C) D) E) Ans:

CH3CHBrCH2CH3 + (CH3)3COK/(CH3)3COH CH3C≡CCH3 + H2, Pt CH3C≡CCH3 + H2, Ni2B (P-2) CH3C≡CCH3 + Na, NH3(l) CH3CHBrCH2CH3 + NaNH2 C

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 135. Which sequence of reagents would be expected to accomplish the transformation shown?

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

1) HBr; 1) Br 2; 1) Br 2, H2O; 1) HBr/ROOR; 1) Na, NH3(l) B

2) 2 NaNH2 2) 2 NaNH2 2) NaNH2 2) excess NaNH2

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate 136. Which sequence of reagents would be expected to to accomplish the transformation of 1-butyne shown below?

A) B) C)

1) H2O/H2SO4, HgSO4 cat.; 1) HBr; 1) H2, Lindlar catalyst;

2) H2, Pt 2) H2, Pt; 2) BH3•THF;

3) NaOH 3) H2O2, NaOH

D) E) Ans:

1) HBr, peroxides; 1) O3 C

2) NaOH; 2) H2O

3) H2, Pt

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate 137. Which sequence of reactions is expected to produce cis-3-octene as the final, and major, organic product?

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

I II III IV V B

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 138. Which sequence of reactions is expected to produce the product below as the final, and major, organic product?

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

1) H2, Lindlar’s cat.; 1) H2, Pt; 1) OsO4; 1) Na, NH3(l); 1) OsO4; A

2) OsO4; 2) OsO4; 2) NaHSO3/H2O; 2) OsO4; 2)NaHSO3/H2O;

3) NaHSO3/H2O 3) NaHSO3/H2O 3) H2, Lindlar’s cat. 3) NaHSO3/H2O 3) Na, NH3(l)

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 139. Which sequence of reactions is expected to produce the product product below as the the final, and major, organic product?

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

1) Na, NH3(l); 1) H2, Lindlar’s cat.; 1) H2, Ni2B (P-2); Both A and B Both A and C D

2) OsO4; 3) NaHSO3/H2O 2) MCPBA; 3) H3O+ 2) KMnO4, NaOH (cold)

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 140. Which sequence of reactions is expected to produce the product below as the final, and major, organic product?

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

1) Br 2; 1) H2, Lindlar’s cat.; 1) Br 2; 1) Na, NH3(l); 1) Br 2, B

2) H2, Lindlar’s cat. 2) Br 2 2) Na, NH3(l) 2) Br 2 2) H2, Pt

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 141. What is the final major product product expected for the following reaction sequence?

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

( R R)-3-chlorohexane (S )-3-chlorohexane )-3-chlorohexane meso-3,4-dichlorohexane (±)-3,4-dichlorohexane 2,3-dichloro-3-hexene D

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 142. What is the final major product product expected for the following reaction sequence?

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

( R R)-3-bromohexane (S )-3-bromohexane )-3-bromohexane meso-3,4-dibromohexane (±)-3,4-dibromohexane 2,3-dibromo-3-hexene C

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Hard 143. Which sequence of reactions is expected to produce the product below as the the final, and major, organic product?

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

I II III IV V A

Conceptual Questions:

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 144. Draw all of the constitutionally isomeric alkynes with molecular formula C5H8.

Ans: Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 145. Provide the IUPAC name for CH3CH(CH3)C(CH3)2C≡CCH(CH3)2. Ans:

2,5,5,6-tetramethyl-3-heptyne or 2,5,5,6-tetramethylhept-3-yne

Topic: Alkyne Nomenclature

Section: 10.2 Difficulty Level: Easy 146. Provide the IUPAC name for CH3C≡CC(CH3)2CH(CH2CH3)2. Ans:

5-ethyl-4,4-dimethyl-2-heptyne or 5-ethyl-4,4-dimethylhept-2-yne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 147. Provide the IUPAC name for CH3CHBrC≡C(CH2)3CH3. Ans:

2-bromo-3-octyne or 2-bromooct-3-yne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 148. Provide the IUPAC name for the following following compound:

Ans:

4-sec-butyl-2-octyne or 4-sec-butyloct-2-yne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 149. Provide the IUPAC name for the following following compound:

Ans:

4,4-dimethyl cyclooctyne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Medium 150. Provide the IUPAC name for the following following compound:

Ans:

(S )-2,3,6,6-tetramethyloct-4-yne )-2,3,6,6-tetramethyloct-4-yne or (S )-2,3,6,6-tetramethyl-4-octyne )-2,3,6,6-tetramethyl-4-octyne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Hard

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

Ans: (3 E ,5 ,5S )-5-fluoro-2-methylnon-3-en-6-yne )-5-fluoro-2-methylnon-3-en-6-yne or (3 E ,5 ,5S )-5-fluoro-2-methyl-3)-5-fluoro-2-methyl-3nonen-6-yne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Hard 152. Provide the IUPAC name for the following compound:

Ans: (4 R,5S )-4-bromo-5-chloro-3-ethylhex-1-yne )-4-bromo-5-chloro-3-ethylhex-1-yne or (4R,5S )-4-bromo-5-chloro)-4-bromo-5-chloro3-ethyl-1-hexyne

Topic: Alkyne Nomenclature Section: 10.2 Difficulty Level: Easy 153. Draw the line-bond structure for the compound with the IUPAC name 2,5,9trimethyl-2-decen-7-yne.

Ans:

Topic: Acidity of Terminal Alkynes Section: 10.3 Difficulty Level: Easy 154. Rank the following hydrocarbons in order of decreasing acidity (most acidic to least acidic).

I

A) B) C) D) E) F)

II

III

I > II > III I > III > II II > III > I II > I > III III > I > II III > II > I

Ans:

F

Topic: Preparation of Alkynes Section: 10.4 Difficulty Level: Easy 155. Describe a sequence of reactions reactions by which which 2-hexyne can be straightforwardly prepared from acetylene. Ans:

1) 2) 3) 4)

NaNH2 CH3Br NaNH2 CH3CH2CH2Br

Or:

1) 2) 3) 4)

NaNH2 CH3CH2CH2Br NaNH2 CH3Br

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 156. What reagent(s) reagent(s) are required required to prepare trans-2-heptene from 2-heptyne? Ans:

Na, NH3(l)

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

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

Ans: H2, Pt

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 158. Provide the reagent(s) expected to accomplish the transformation transformation shown below:

Ans: H2, Ni2B or Lindlar’s catalyst

Topic: Reduction of Alkynes Section: 10.5 Difficulty Level: Easy 159. Determine which compound will will react with with sodium in liquid ammonia to form trans-3-hexene. A) B) C) D) E)

cis-3-hexene trans-2-hexene 3-hexyne 2-hexyne cis-2-hexene

Ans: C Topic: Hydrohalogenation of Alkynes Section: 10.6 Difficulty Level: Moderate 160. Provide the structure(s) structure(s) of the expected major organic product(s) product(s) from the following reaction:

Ans:

and

Topic: Hydration of Alkynes Section: 10.7 Difficulty Level: Easy 161. Provide the structure(s) structure(s) of the expected major organic product product from the following reaction:

Ans:

Topic: Ozonolysis of Alkynes Section: 10.9 Difficulty Level: Easy 162. Provide the structure(s) structure(s) of the expected major organic product(s) product(s) from the following reaction:

Ans:

and

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Easy 163. Provide the structure(s) structure(s) of the expected major organic product from the following following reaction sequence:

Ans:

Topic: Synthetic Strategies Section: 10.11 Difficulty Level: Moderate 164. Why would the following synthetic route shown below be unsuccessful?

Ans: The alkynide anion formed by reaction with with sodium amide will facilitate facilitate an E2 (rather than S N2) reaction with t -butyl -butyl bromide.

Topic: Integrated Section: 10.2 Difficulty Level: Medium 165. Draw all constitutional isomers isomers of the molecular formula C6H10 that are internal alkynes. Ans:

Topic: Integrated Section: 10.2 Difficulty Level: Medium 166. Draw all constitutional isomers isomers of the molecular formula C6H10 that are terminal alkynes.

Ans:

Topic: Preparation of Alkynes + Spectroscopy Section: 10.4 + Spectroscopy Difficulty Level: Hard 167. Compound X, a geminal dihalide, is exposed to to excess strong strong base (excess NaNH NaNH2 then H2O) to produce an alkyne (compound Y). Alkyne Y is a terminal terminal alkyne, has a molecular formula of C5H8, and has exactly 4 distinct resonances in the (protondecoupled) 13C NMR spectrum. What are the two possible structures for compound X?

Ans:

Topic: Preparation of Alkynes + Spectroscopy Section: 10.4 + Spectroscopy Difficulty Level: Hard 168. 1-Pentyne was exposed to strong base (NaNH2) then alkyl halide X, producing an internal alkyne (compound Y). Alkyne Y has exactly 4 distinct resonances resonances in the 13 (proton-decoupled) C NMR spectrum. What are the structures structures of alkyl halide X, as well as alkyne Y?

Ans:

ch10-testbank

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