Deck 7: Alkynes

Question 1

What is the major organic product obtained from the following reaction? $\mathrm{CH}_{3} \mathrm{CHBrCHBrCH}_{3}$$\underset{\mathrm{DMSO}}{\stackrel{\mathrm{NaNH}_{2}}{\longrightarrow}}$

A) (E) 2-butene
B) (Z) 2-butene
C) 2-butyne
D) 1-butyne

Answer 1

2-butyne

Question 2

Which of the following is the strongest acid?

A) propane
B) cyclopropane
C) propene
D) propyne

Answer 2

propyne

Question 3

What is the IUPAC name of the following compound? (CH₃)₂CHCH₂−C≡C−CH(CH₃)₂

A) 2,6-dimethyl-3-heptyne
B) 2,6-dimethyl-4-heptyne
C) 1,1,5,5-tetramethyl-2-pentyne
D) 4-nonyne

Answer 3

2,6-dimethyl-3-heptyne

Question 4

Approximately how long is a carbon-carbon triple bond of an alkyne?

A) 110 pm
B) 121 pm
C) 135 pm
D) 156 pm

Question 5

What is the approximate C−C−C bond angle in propyne?

A) 90°
B) 109°
C) 120°
D) 180°

Question 6

What is the IUPAC name of the following compound?

A) (R)-4-methyl-2-hexyne
B) (S)-4-methyl-2-hexyne
C) (R)-3-methyl-4-hexyne
D) (S)-3-methyl-4-hexyne

Question 7

Which atomic orbitals overlap to form the carbon-carbon triple bond of an alkyne?

A) 2s + 2s; sp + sp; 2p + 2p
B) sp + sp; sp + sp; 2p + 2p
C) sp + sp; 2p + 2p; 2p + 2p
D) sp² + sp²; sp + sp; 2p + 2p

Question 8

Which of the following has the lowest pK_a?

A) butane
B) 1-butene
C) 1-butyne
D) 2-butyne

Question 9

What is the major organic product obtained from the following reaction?

A) cyclohexyne
B) 1,3-cyclohexadiene
C) cyclohexene
D) 1,2-diaminocyclohexane

Question 10

What is the correct assignment of the acid, base, conjugate acid and conjugate base in the following equilibrium?

A) 1 = acid; 2 = base; 3 = conjugate acid; 4 = conjugate base
B) 1 = acid; 2 = base; 3 = conjugate base; 4 = conjugate acid
C) 1 = base; 2 = acid; 3 = conjugate acid; 4 = conjugate base
D) 1 = base; 2 = acid; 3 = conjugate base; 4 = conjugate acid

Question 11

What is the IUPAC name of the following compound? CH₃CH₂CH₂−C≡C−CH(CH₃)₂

A) 1-isopropyl-1-pentyne
B) 2-methyl-3-heptyne
C) 6-methyl-4-heptyne
D) isopropyl propyl ethyne

Question 12

How many terminal alkynes are there with the molecular formula C₇H₁₂?

A) 5
B) 7
C) 8
D) 9

Question 13

What is the smallest cycloalkyne that is stable at room temperature?

A) cyclohexyne
B) cyclononyne
C) cyclododecyne
D) cycloeicosyne

Question 14

What is the IUPAC name for the following compound?

A) (R)-3-methyl-1-penten-4-yne
B) (S)-3-methyl-1-penten-4-yne
C) (R)-4-methyl-4-penten-1-yne
D) (S)-4-methyl-4-penten-1-yne

Question 15

What is the IUPAC name of the following compound?

A) 3,4-dimethyl-1-hexen-5-yne
B) 4-ethynyl-2-vinylbutane
C) 3-methyl-4-vinyl-1-pentyne
D) 4-ethynyl-3-methyl-1-pentyne

Question 16

Which sequence of reactions can be used to convert (Z) 2-pentene to 2-pentyne

A) Treatment with Br₂; followed by treatment with NaNH₂
B) Treatment with Br₂, H₂O; followed by treatment with NaOH
C) Treatment with Br₂; followed by treatment with H₂SO₄
D) Treatment with HBr; followed by treatment with NaOH

Question 17

Which sequence of reactions can be used to convert 1-pentene to 1-pentyne

A) Treatment with HBr; followed by treatment with NaOH
B) Treatment with Br₂; followed by treatment with NaNH₂
C) Treatment with Br₂; followed by treatment with H₂SO₄
D) Treatment with Br₂, H₂O; followed by treatment with NaOH

Question 18

What is the IUPAC name of the following compound

A) vinylcyclohexane
B) allylcyclohexane
C) ethynylcyclohexane
D) acetylcyclohexane

Question 19

How many alkynes are there with the molecular formula C₆H₁₀?

A) 4
B) 5
C) 6
D) 7

Question 20

Which atomic orbitals overlap to form the carbon-carbon single bond of 1-propyne?

A) 2s + sp
B) sp + sp²
C) sp + sp³
D) sp² + sp³

Question 21

What is the major organic product obtained from the following reaction? $$\mathrm { CH } _ { 3 } - \mathrm { C } \equiv \mathrm { C } - \mathrm { CH } _ { 3 } \stackrel { 2 \mathrm {~mol} \mathrm { HBr } } { \longrightarrow }$$

A) 2,3-dibromobutane
B) 2,2,3,3-tetrabromobutane
C) 2,3-dibromobutene
D) 2,2-dibromobutane

Question 22

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 23

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 24

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 25

What is the major organic product obtained from the following reaction?

A) (E) 3,4-dibromohexene
B) (Z) 3,4-dibromohexene
C) (E) 2,3-dibromohexene
D) (Z) 2,3-dibromobutene

Question 26

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 27

What is the major organic product obtained from the following reaction? $\stackrel{2 \mathrm{~mol} \mathrm{Br}_{2}}{\longrightarrow}$

A) 3,4-dibromohexane
B) 3,3-dibromohexane
C) (Z) 3,4-dibromohexene
D) 3,3,4,4-tetrabromohexane

Question 28

What type of intermediate is formed in the Hg²⁺ catalyzed hydration of an alkyne??

A) an alcohol
B) an enol
C) a 1,2-diene
D) an epoxide

Question 29

What is the major organic product obtained from the following reaction?

A) butanal
B) cis-2-butene
C) 2-butanol
D) butanone

Question 30

What is the major organic product obtained from the following reaction?

A) butanal
B) cis-2-butene
C) 2-butanol
D) butanone

Question 31

What is the major organic product obtained from the following reaction? $\mathrm{CH}_{3}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_{3}$$\stackrel{2 \mathrm{~mol} \mathrm{Br}_{2}}{\longrightarrow}$

A) 2,3-dibromobutane
B) 2,2,3,3-tetrabromobutane
C) 2,3-dibromobutene
D) 2,2-dibromobutane

Question 32

What is the major organic product obtained from the following reaction?

A) (E) 1,2-dibromobutene
B) (Z) 1,2-dibromobutene
C) (E) 2,3-dibromobutene
D) (Z) 2,3-dibromobutene

Question 33

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 34

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 35

What is the major organic product obtained from the following reaction?

A) 2-hexanone
B) hexanal
C) 2-hexanol
D) cis-2-hexene

Question 36

What is the major organic product obtained from the following reaction?

A) 1-methyl-4-nonyne
B) 2-methyl-4-nonyne
C) 2-methyl-3-nonyne
D) 3-methyl-4-nonyne

Question 37

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 38

What is the major organic product obtained from the following reaction? $\text { 1. } \underset{\mathrm{NaNH}_{2}}{\stackrel{\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}}{\longrightarrow}}$

A) 2-methyl-3-hexene
B) 2-methyl-3-heptyne
C) 2-bromo-3-methylbutane
D) 2-methyl-2-butene

Question 39

What is the major organic product obtained from the following reaction?

A) 2-hexanone
B) hexanal
C) 2-hexanol
D) cis-2-hexene

Question 40

What is the major organic product obtained from the following reaction? $\stackrel{2 \mathrm{~mol} \mathrm{HBr}}{\longrightarrow}$

A) 3,4-dibromohexane
B) 3,3-dibromohexane
C) (E) 3,4-dibromohexene
D) 3,3,4,4-tetrabromohexane

Question 41

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 42

What is the major organic product obtained from the following series of reactions?

A) propanal, CH₃CH₂CHO
B) 1-propanol, CH₃CH₂CH₂OH
C) butanal, CH₃CH₂CH₂CHO
D) butanone, CH₃COCH₂CH₃

Question 43

What is the best choice of reagent(s) to perform the following transformation?

A) H₂/Pt
B) H₂/Lindlar catalyst
C) Na/NH₃
D) BH₃; followed by H₂O₂, NaOH

Question 44

What is the major organic product obtained from the following series of reactions?

A) (Z)-2-heptene
B) (Z)-1,5-heptene
C) 1-heptene
D) heptane

Question 45

What is the major organic product obtained from the following series of reactions?

A) (E)-5-phenyl-2-pentene
B) 6-phenyl-1-hexene
C) (Z)-6-phenyl-2-hexene
D) (E)-6-methyl-3-heptene

Question 46

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 47

The triple bond in ethyne is made up of two π bonds, each formed by lateral overlap of two p orbitals, and a σ bond formed by end-on overlap of two sp hybrid orbitals.

Question 48

What is the best choice of reagent(s) to perform the following transformation?

A) 1 mol of Br₂
B) 2 mol of Br₂
C) 1 mol of HBr
D) 2 mol of HBr

Question 49

What is the best choice of reagent(s) to perform the following transformation?

A) H₂/Lindlar catalyst
B) Na/NH₃
C) (sia)₂BH; followed by H₂O₂, NaOH
D) BH₃; followed by H₂O₂, NaOH

Question 50

What is the major organic product obtained from the following reaction?

A) 1
B) 2
C) 3
D) 4

Question 51

Which of the following reagents react with 2-butyne to form butane

A) H₂/Lindlar catalyst
B) H₂/Pd
C) (sia)₂BH followed by CH₃COOH
D) Na/NH₃

Question 52

What is the major organic product obtained from the following reaction?

A) butane
B) 1-butene
C) cis-2-butene
D) trans-2-butene

Question 53

What is the best choice of reagent(s) to perform the following transformation?

A) H₂/Pt
B) H₂/Lindlar catalyst
C) Na/NH₃
D) BH₃; followed by H₂O₂, NaOH

Question 54

What is the major organic product obtained from the following series of reactions?

A) 1
B) 2
C) 3
D) 4

Question 55

What is the best choice of reagent(s) to perform the following transformation?

A) H₂/Lindlar catalyst
B) Na/NH₃
C) (sia)₂BH; followed by H₂O₂, NaOH
D) BH₃; followed by H₂O₂, NaOH

Question 56

What is the major organic product obtained from the following reaction?

A) butane
B) 1-butene
C) cis-2-butene
D) trans-2-butene

Question 57

What is the best choice of reagent(s) to perform the following transformation?

A) 1 mol of Br₂
B) 2 mol of Br₂
C) 1 mol of HBr
D) 2 mol of HBr

Question 58

What is the major organic product obtained from the following series of reactions?

A) (Z)-2-heptene
B) (E)-2-heptene
C) 1-heptene
D) heptane

Question 59

What is the major organic product obtained from the following reaction?

A) butane
B) 1-butene
C) cis-2-butene
D) trans-2-butene

Question 60

The IUPAC name for the following compound is 2,5-dimethyl-4-ethyl-3-hexene.

Question 61

What is the major organic product obtained from the following reaction?

Question 62

2-hexyne will produce a single product upon mercury(II)-catalyzed hydration.

Question 63

The following species is referred to as a(an)_________________.

Question 64

The key intermediate in the following reaction would be a vinylic carbocation. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\mathrm{Br}$
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ |
$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}$$\underset{\mathrm{CH}_{3} \mathrm{COOH}}{\stackrel{\mathrm{HBr}}{\longrightarrow}}$$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}-\mathrm{C}=\mathrm{CH}_{2}$

Question 65

Acetylene (ethyne) is more acidic and has a shorter carbon to carbon bond than either ethane or ethene.

Question 66

The product of the reaction when the following substance is treated with BH₃ in THF followed by H₂O₂ would be a ketone.

Question 67

What is IUPAC name of the following compound?

Question 68

Addition of H₂ to 2-pentyne in the presence of the Lindlar's catalyst will produce ___-2-pentene.

Question 69

The following deuteration reaction correctly shows the stereochemistry of the product.

Question 70

What is IUPAC name of the following compound?

Question 71

The following species is the conjugate base of _________________.

Question 72

Consider an unknown with the molecular formula C₄H₆. The number of possible alkyne isomers is _____.

Question 73

The product of the following reaction would be an aldehyde.

Question 74

Consider an unknown with the molecular formula C₄H₆. The index of hydrogen deficiency of this compound is _____.

Question 75

The name of the product of the reaction of the following substance with bromoethane would be ________________.

Question 76

What is IUPAC name of the following compound?

Question 77

H₂ and Ni would be the required reagents for the following conversion.

Question 78

Consider the following, the product formed is shown below.

Question 79

The name of the final product after adding 1 mole of each reactant in the following sequence is ______________________.

Question 80

What is IUPAC name of the following compound?