Deck 3: Alkenes and Alkynes

Question 1

Which of the following molecular formulas could not represent an alkene?

A) C₅H₁₀
B) C₇H₁₄
C) C₁₀H₂₀
D) C₂₇H₅₆
E) C₃₁H₆₂

Answer 1

C₂₇H₅₆

Question 2

Which of the following molecules is 4-methyl-2-hexyne?

A)
B)
C)
D)
E)

Answer 2

Question 3

The multiple bonds in the following compounds are conjugated:

A) 2, 3, and 5
B) 4 and 6
C) only 1
D) 2 and 3
E) 2 and 5

Answer 3

2, 3, and 5

Question 4

What is the percent s character in an sp hybrid orbital?

A) 25%
B) 33%
C) 50%
D) 67%
E) 75%

Question 5

Which of the following dienes can be classified as conjugated?

A)CH₃CH=C=CH₂
B)CH₃CH=CHCH=CH₂
C)CH₂=CHCH₂CH=CH₂
D)CH₃CH=CHCH₂CH₂CH=CH₂
E)CH₂=C=CH₂

Question 6

Which of the following hydrocarbons will be the most acidic?

A) pentane
B) ethene
C) acetylene
D) isobutane
E) propylene

Question 7

What is the correct structure for 2,3-dimethyl-2-pentene?

A)
B)
C)
D)
E)

Question 8

Which of the following statements are true about acetylene (ethyne)?

A) It is more acidic than ethane and ethene.
B) The bond angle around the carbon-carbon triple bond is 180°.
C) The carbon-carbon triple bond is shorter than the carbon-carbon double bond.
D) All of the above are true.
E) None of the above are true.

Question 9

The correct IUPAC name for the following molecule is:

A) trans-2,3-dichloro-5-methyl-2-hexene
B) trans-2,3-dichloro-5-methyl-3-hexene
C) cis-2,3-dichloro-5-methyl-3-hexene
D) trans-4,5-dichloro-2-methyl-4-hexene
E) cis-4,5-dichloro-2-methyl-4-hexene

Question 10

What is the percent s character in an sp² hybrid orbital?

A) 25%
B) 33%
C) 50%
D) 67%
E) 75%

Question 11

Which of the following statements is false relative to alkenes?

A) the C of the carbon-carbon double bond is sp² hybridized
B) the bond angles are approximately 120° around the carbon-carbon double bond
C) there is the possibility of cis/trans isomerism
D) they are more reactive than alkanes
E) the bond length of the carbon-carbon double bond is longer than that of the carbon-carbon single bond

Question 12

The correct name of the molecule below is:

A) 5-methyl-7-octen-1-yne
B) 4-methyl-1-octen-7-yne
C) 4-methyl-1-octyn-7-ene
D) 5-methyl-1-octen-7-yne
E) none of these is correct

Question 13

Which of the following compounds can exhibit cis/trans isomerism?

A) 1-heptene
B) 2-heptene
C) 2-methyl-2-hexene
D) 3-methyl-1-hexene
E) 3-ethyl-2-pentene

Question 14

Which compound contains a carbon-carbon double bond with (Z) stereochemistry?

A)
B)
C)
D)
E)

Question 15

The double bond in ethene is made up of

A) a pi bond and a sigma bond formed by lateral overlap of two p orbitals.
B) a sigma bond formed by overlap of two s orbitals and a pi bond formed by lateral overlap of two p orbitals.
C) a pi bond formed by end-on overlap of two sp² orbitals and a sigma bond formed by overlap of two s orbitals.
D) a sigma bond formed by end-on overlap of two sp² orbitals and a pi bond formed by lateral overlap of two p orbitals.
E) a pi bond formed by lateral overlap of two sp² orbitals and a sigma bond formed by end-on overlap of two sp² orbitals.

Question 16

The structure of (Z)-3-methyl-2-pentene is

A)
B)
C)
D)
E)

Question 17

What is the correct name for the following molecule?

A) 1-ethylcyclohexene
B) 2-ethylcyclohexene
C) 3-ethylcyclohexene
D) cyclohexylethane
E) 1-ethyl-3-cyclohexene

Question 18

The triple bond in ethyne is made up of

A) two pi bonds and a sigma bond, each formed by a lateral overlap of two p orbitals.
B) a sigma bond formed by overlap of two s orbitals and two pi bonds, each formed by lateral overlap of two p orbitals.
C) a sigma bond formed by end-on overlap of two sp² orbitals and a pi bond formed by lateral overlap of two p orbitals.
D) two pi bonds, each formed by lateral overlap of two p orbitals, and a sigma bond formed by end-on overlap of two sp orbitals.
E) two pi bonds, each formed by end-on overlap of two p orbitals, and a sigma bond formed by lateral overlap of two sp orbitals.

Question 19

The correct name for is:

A) 2-methyl-4-isopropyl-3-hexene.
B) 3-ethyl-2,5-dimethyl-3-hexene.
C) 2,5-dimethyl-4-ethyl-3-hexene.
D) 1-ethyl-1,2-diisopropylethene.
E) 1,2-diisopropyl-1-butene.

Question 20

The correct structure for allyl bromide is:

A)
B)
C)
D)
E)

Question 21

Select the necessary reagents to convert 1-methylcyclopentene to 1-methylcyclopentanol.

A) H₂O and H₂SO₄
B) Zn, H₂O
C) BH₃, then H₂O₂ and ^-OH
D) O₃, then Zn, H⁺
E) KOH in alcohol and heat

Question 22

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

A) pentane
B) 1-pentene
C) cis-2-pentene
D) trans-2-pentene

Question 23

The products of the following reaction sequence are

A)
B)
C)
D)
E)

Question 24

The product of the reaction is:

A)
B)
C)
D)
E)

Question 25

What is the product for the reaction below?

A)
B)
C)
D)
E)

Question 26

The products obtained by the acid-catalyzed hydration of 1-methylcyclohexene and methylenecyclohexene are

A) identical.
B) regioisomers.
C) cis-trans isomers.
D) constitutional isomers.
E) none of the above.

Question 27

The Diels-Alder reaction is very important in the synthesis of six-membered rings.What six-membered ring is produced with the following reaction?

A)
B)
C)
D)
E)

Question 28

What is observed when water, in the presence of sulfuric acid, is added to 2-methyl-2-pentene?

A)
B)
C)
D)
E)

Question 29

Select the necessary reagent(s) to convert cycloheptene to cycloheptane.

A) H₂ and Ni
B) H₂O
C) H₂SO₄ and heat
D) Zn and H⁺
E) KOH in alcohol and heat

Question 30

Upon ozonolysis and treatment with Zn in water, compound A yielded two moles of formaldehyde, HCHO, and 1 mole of the following molecule: What is the structure of A?

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

Question 31

The product of the reaction is

A)
B)
C)
D)
E)

Question 32

What product(s) will be observed by the addition of one molar equivalent of Br₂ to ________________ 1,3-cyclohexadiene?

A) 1,2-dibromocyclohexene
B) 3,4-dibromocyclohexene
C) 1,3-dibromocyclohexene
D) 3,6-dibromocyclohexene
E) both b and d

Question 33

The product of the reaction sequence is

A)
B)
C)
D)
E) none of the above

Question 34

What would be the major product of the following reaction?

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

Question 35

What is the name of the product formed from the following reaction?

A) bromocyclopentane
B) 1,1-dibromocyclopentane
C) cis-1,2-dibromocyclopentane
D) trans-1,2-dibromocyclopentane
E) 1,1-dibromocyclopentene

Question 36

What is the product for the reaction below?

A)
B)
C)
D)
E) none of these

Question 37

The products obtained by adding 1 mole of HBr to 2,4-hexadiene are

A) 4-bromo-2-hexene and 5-bromo-2-hexene.
B) 3-bromo-2-hexene and 4-bromo-2-hexene.
C) 4-bromo-2-hexene and 2-bromo-4-hexene.
D) 2-bromo-3-hexene and 3-bromo-2-hexene.
E) 2-bromo-3-hexene and 4-bromo-2-hexene.

Question 38

The product of the reaction is:

A)
B)
C)
D)
E)

Question 39

The product of addition of two moles of HBr to 1,4-pentadiene is

A) 2,2-dibromopentane.
B) 2,4-dibromopentane.
C) 1,5-dibromopentane.
D) 3,3-dibromopentane.
E) 1,4-dibromopentane.

Question 40

What type of compound is prepared by adding water to propyne in the presence of sulfuric acid and mercuric sulfate?

A) aldehyde
B) ketone
C) carboxylic acid
D) ester
E) ether

Question 41

Upon ozonolysis which alkene will give only acetone, (CH₃)₂C=O?

A) 2,3-dimethyl-2-butene
B) 2,2-dimethyl-2-butene
C) 3-hexene
D) 2-methyl-2-pentene
E) 2-methyl-3-hexene

Question 42

What is/are the final product(s) in the following multistep synthesis?

A) I
B) II
C) III
D) I and II
E) all are produced

Question 43

What is the name of the alkene produced by treating 1-butyne with 1 mole of Br₂?

A) (E)-1,2-dibromo-1-butene
B) 1,1-dibromo-1-butene
C) (Z)-1,2-dibromo-1-butene
D) 1,2-dibromo-1-butene
E) none of the above

Question 44

What alkene is required to make 3-methyl-1-butanol using the hydroboration-oxidation reaction?

A) 1-butene
B) 2-butene
C) 3-methyl-1-butene
D) 2-methyl-2-butene
E) 2-methyl-1-butene

Question 45

Which of the following alkenes is needed to prepare 3-cyclohexyl-1-propanol via a hydroboration-oxidation reaction? 3-cyclohexyl-1-propanol

A) cyclohexene
B) vinyl cyclohexane
C) allyl cyclohexane
D) propyl cyclohexene
E) 1- octene

Question 46

What is the final product of adding 1 mole of each reactant in the following sequence?

A) propyl chloride
B) propyl bromide
C) 1-bromo-2-chloropropane
D) 2-bromo-2-chloropropane
E) 2,2-dibromopropane

Question 47

What type of carbocation will form from the addition of a H⁺ to 2-methylpropene?

A) H₃C⁺
B) 1°
C) 2°
D) 3°
E) allyl

Question 48

Polyethylene is usually produced by

A) an ionic electrophilic addition reaction
B) heating ethylene to 1000^oC.
C) cationic polymerization.
D) a free-radical chain reaction.
E) epoxidation.

Question 49

The first step in the free radical mechanism for the preparation of polyethylene is:

A) formation of a stable carbocation
B) formation of a stable carbanion
C) heating an organic peroxide to break the O-O bond
D) decoupling of the free radicals
E) propagation of the free radicals

Question 50

Which of the following reagents can be used to distinguish cyclohexene from cyclohexane?

A) Zn, H⁺
B) H₂O
C) Cl₂, h $v$
D) Br₂, CCl₄
E) O₂, heat

Question 51

Markovnikov addition of HCl to propene involves:

A) initial attack by the chloride ion
B) initial attack by the chlorine atom
C) isomerization of 1-chloropropane
D) formation of a propyl cation
E) formation of an isopropyl cation

Question 52

Cyclohexene is treated with cold dilute KMnO₄.What is the spatial arrangement of the hydroxyls on the resulting cyclohexane ring?

A) 1,2-cis
B) 1,2-trans
C) 1,4-cis
D) 1,4-trans
E) a mixture of 1,2-cis and 1,2-trans