Deck 7: The Reactions of Alkynes - Introduction to Multistep Synthesis

Question 1

What is the common name for the following alkyne?

A)neohexyne
B)trimethylpropyne
C)trimethylacetylene
D)tert-butylacetylene
E)isopropylacetylene

Answer 1

tert-butylacetylene

Question 2

Give the IUPAC name for the following compound.

A)isoprene
B)3-methyl-1,3-butadiene
C)2-methyl-1,3-butadiene
D)2-methyl-2,3-butadiene
E)isobutadiene

Answer 2

2-methyl-1,3-butadiene

Question 3

Draw an acceptable structure for acetylene.

Answer 3

H-C C-H

Question 4

Name the following compound.

Question 5

Provide an acceptable name for the compound shown.

Question 6

How many distinct internal alkynes exist with a molecular formula of C₆H₁₀?

A)1
B)2
C)3
D)4
E)5

Question 7

Give the IUPAC name for BrCH₂CH₂CCCH₂CH₃.

Question 8

Write structures and give IUPAC names for all alkynes with molecular formula C₅H₈.

Question 9

Give the IUPAC name for HCCCH₂CH₂CH₃.

Question 10

What is the IUPAC name for the following alkyne?

A)5-Bromo-2-heptyne
B)3-Bromo-5-heptyne
C)2-Bromo-2-methyl-4-hexyne
D)5-Bromo-5,5-dimethylhexyne
E)5-Bromo-5-methyl-2-hexyne

Question 11

Give the systematic name of the compound shown below.

Question 12

Provide the structure of all distinct terminal alkynes with a molecular formula of C₆H₁₀.

Question 13

Name the following compound.

A)3-heptyn-6-ol
B)3-hepten-6-ol
C)4-hepten-2-ol
D)4-heptyn-2-ol
E)4-heptan-2-ol

Question 14

Provide the systematic name of the compound shown.

Question 15

Draw an acceptable structure for 3-sec-butyl-1-heptyne.

Question 16

How many distinct terminal alkynes exist with a molecular formula of C₅H₈?

A)1
B)2
C)3
D)4
E)5

Question 17

Give the IUPAC name for (CH₃)₂C(CH₂CH₃)CCCH(CH₃)₂.

Question 18

Give the systematic name for the alkyne Cl₃CCH₂CH₂CCCH₃.

Question 19

Draw an acceptable structure for 2-hexyne.

Question 20

What is the IUPAC name for the following compound?

A)cis,trans-2,4-heptadiene
B)2Z,4Z-2,4-heptadiene
C)cis,cis-2,4-heptadiene
D)trans,trans-2,4-heptadiene
E)2E,4E-2,4-heptadiene

Question 21

What are the hybridizations of the carbon atoms numbered 1 and 2 in the structure below? 1 2
H₃C-CH CH-C C-H

A)sp³,sp²
B)sp²,sp²
C)sp²,sp
D)sp,sp

Question 22

________ is produced when 1 equivalent of HBr is added to 1-hexyne.

A)2-bromo-1-hexene
B)E-1-bromo-1-hexene
C)Z-1-bromo-1-hexene
D)A mixture of E and Z isomers of 1-bromo-1-hexene
E)E-2-bromo-2-hexene

Question 23

Although you might expect 1-propyne to be more reactive than 1-propene in electrophilic addition reactions,the reverse is true.Explain this using your knowledge of the mechanism of electrophilic additions to both alkynes and alkenes.

Question 24

Provide the systematic name of the compound shown.

Question 25

Which of the following improperly describes the physical properties of an alkyne?

A)relatively nonpolar
B)nearly insoluble in water
C)less dense than water
D)insoluble in most organic solvents

Question 26

In the addition of hydrogen bromide to alkynes in the absence of peroxides,which of the following species is believed to be an intermediate?

A)vinyl anion
B)vinyl cation
C)vinyl radical
D)carbene
E)bromonium ion

Question 27

The carbon-carbon triple bond of an alkyne is composed of

A)three σ bonds.
B)two σ bonds and one π bond.
C)one σ bond and two π bonds.
D)three π bonds.

Question 28

Provide the structure of the major organic product of the following reaction.

Question 29

Provide the structure of the major organic product of the following reaction.

Question 30

Which of the following statements correctly describes the general reactivity of alkynes?

A)An alkyne is an electron-rich molecule and therefore reacts as a nucleophile.
B)The σ bonds of alkynes are higher in energy than the π bonds and are thus more reactive.
C)Unlike alkenes,alkynes fail to undergo electrophilic addition reactions.
D)Alkynes are generally more reactive than alkenes.
E)Alkynes react as electrophiles,whereas alkenes reacts as nucleophiles.

Question 31

Name the following compound.

Question 32

Give the systematic name of the compound shown below.

Question 33

Which of the following statements is not true about propyne,HC C-CH₃?

A)It contains six sigma bonds.
B)It contains three pi bonds.
C)The H-C-H bond angle is about 109.5°.
D)The C-C-C bond angle is 180°.
E)The pi bond is weaker than the sigma bond.

Question 34

What are the hybridizations of the carbon atoms numbered 1 and 2 respectively in the following structure?

A)sp³,sp²
B)sp²,sp²
C)sp,sp
D)sp²,sp
E)sp,sp²

Question 35

Provide the structure of (2E,4E)-2-chloro-2,4-octadiene.

Question 36

Which of the following compounds is the major product when 1-hexyne is treated with excess HBr?

A)1,1-dibromohexane
B)1,1-dibromohexene
C)1,2-dibromohexene
D)1,2-dibromohexane
E)2,2-dibromohexane

Question 37

Provide the structure of the major organic product(s)in the reaction below.

Question 38

Which of the following is the best synthesis of 2,2-dibromopropane?

A)CH₃CH CH₂
B)CH₃CH CH₂
C)CH₃C CH
D)CH₃C CH
E)CH₃CH CH₂

Question 39

What two atomic orbitals or hybrid atomic orbitals overlap to form the carbon-carbon σ bond in ethyne?

A)sp³-sp³
B)p-p
C)sp²-sp²
D)s-s
E)sp-sp

Question 40

What is the major product of the following reaction? CH₃C CH

A)
B)
C)CH₃CH CH-Cl
D)
E)

Question 41

Which of the following are enol forms of 2-butanone?

A)
B)
C)
D)
E)

Question 42

Give the major organic product for the reaction.

A)
B)
C)
D)
E)

Question 43

Provide the structure of the major organic product that results when 2-butyne is treated with 1 equivalent of HCl.

Question 44

Which of the following is the final and major product of this reaction?

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

Question 45

Provide the structure of the major organic product(s)in the reaction below.

Question 46

Provide the major organic product in the reaction below.

Question 47

Provide the structure of the major organic product of the following reaction.

Question 48

Provide the major organic product in the reaction below.

Question 49

Provide the structure of the major organic product that results when 2-butyne is treated with 2 equivalents of HCl.

Question 50

Give the major organic product for the reaction.

A)
B)
C)
D)
E)

Question 51

Provide the major organic product in the reaction below.

Question 52

For the reaction below indicate whether the equilibrium constant will be greater than 1 or less than 1.

Question 53

Provide the structure of the intermediate which forms in the first step of the reaction of 1-butyne with water in the presence of H₂SO₄/HgSO₄.

Question 54

Provide the major organic product in the reaction below.

Question 55

Provide the structure of the major organic product that results when 2-butyne is treated with 1 equivalent of Br₂.

Question 56

Provide the major organic product in the reaction below.

Question 57

Provide the major organic product in the reaction below.

Question 58

Give the best reagents for the reaction.

A)H₂SO₄,HgSO₄,HgSO₄
B)1)disiamylborane,2.HO^-,H₂O,H₂O₂
C)K₂Cr₂O₇,H⁺
D)NaOCl
E)H₂,Pd

Question 59

Give the major organic product for the reaction.

A)
B)
C)
D)CH₃CH₂CH₂CH CHOH
E)

Question 60

Which of the following is the final and major product of this reaction?

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

Question 61

Provide the structure of the major organic product of the following reaction.

Question 62

Which of the alkyne addition reactions below involves an enol intermediate?

A)hydroboration/oxidation
B)treatment with HgSO₄ in dilute H₂SO₄
C)hydrogenation
D)both A and B
E)both A and C

Question 63

A mixture of 1-heptyne,2-heptyne,and 3-heptyne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased.If one assumes that the hydrogenation went to completion,how many distinct seven-carbon hydrocarbons were produced?

A)1
B)2
C)3
D)6
E)8

Question 64

Provide the structure of the major organic product(s)in the reaction below.

Question 65

Provide the structure of the major organic product that results when 2-butyne is treated with HgSO₄/H₂SO₄ in water.

Question 66

Provide the structure of the major organic product of the following reaction.

Question 67

Provide the structure of the major organic product of the following reaction.

Question 68

In the reduction of alkynes using sodium in liquid ammonia,which of the species below is not an intermediate in the commonly accepted mechanism?

A)vinyl anion
B)vinyl radical
C)radical anion
D)vinyl cation

Question 69

The reagent needed to convert 2-butyne to trans-2-butene is

A)H₂/Pt.
B)H₂/Lindlar's catalyst.
C)Li/NH₃.
D)Na/NH₃.
E)C or D.

Question 70

An optically active compound (A),C₆H₁₀,reacts with H₂/Ni to produce compound (B),C₆H₁₄.(B)is optically inactive.Deduce the structures of (A)and (B).

Question 71

Give the best reagents for the reaction.

A)H₂SO₄,HgSO₄,HgSO₄
B)1)disiamylborane,2.HO^-,H₂O,H₂O₂
C)K₂Cr₂O₇,H⁺
D)NaOCl
E)H₂,Pd

Question 72

Provide the structure of the major organic product of the following reaction.

Question 73

Provide the structure of the major organic product(s)in the reaction below.
CH₃CH₂-C C-CH₃

Question 74

The reagent needed to convert 2-butyne to cis-2-butene is

A)H₂/Pt.
B)H₂/Lindlar's catalyst.
C)Li/NH₃.
D)Na/NH₃.
E)H⁺/Zinc dust.

Question 75

Complete the following reaction.
3-hexyne

Question 76

Provide the structure of the major organic product(s)in the reaction below.

Question 77

Give the major organic product for the reaction.

A)
B)
C)
D)CH₃CH₂CH₂CH CHOH
E)

Question 78

Provide the major organic product in the reaction below.

Question 79

Complete the following reaction.

Question 80

Provide the major organic product in the reaction below.