Alkenes and Alkynes: Structure, Properties, and Reactions

Question 1

Which type of reaction is most characteristic of alkenes?

Accepted Answer

Electrophilic addition

Answer

Nucleophilic substitution

Answer

Free radical substitution

Answer

SN2 reaction

Question 2

Which of the following is a physical property of alkenes?

Accepted Answer

Low boiling points

Answer

High density

Answer

Solubility in water

Answer

Metallic luster

Question 3

What type of isomerism is exhibited by the following pair of compounds: cis-2-butene and trans-2-butene?

Accepted Answer

Geometric isomerism

Answer

Structural isomerism

Answer

Stereoisomerism

Answer

Enantiomerism

Question 4

Which type of orbital overlap is responsible for forming the pi bond in an alkene?

Accepted Answer

p-p overlap

Answer

s-s overlap

Answer

s-p overlap

Answer

d-d overlap

Question 5

What causes the cis-trans isomerism observed in alkenes?

Accepted Answer

Restricted rotation about the double bond

Answer

Different hybridization of carbon atoms

Answer

Different functional groups attached to the double bond

Answer

Different molecular weights

Question 6

Identify the incorrect statement about alkynes.

Accepted Answer

Alkynes cannot undergo electrophilic addition reactions.

Answer

Alkynes contain at least one carbon-carbon triple bond.

Answer

Alkynes are more reactive than alkenes.

Answer

Alkynes are linear hydrocarbons.

Question 7

What is the hybridization of the carbon atoms in the triple bond of an alkyne?

Accepted Answer

sp

Answer

sp2

Answer

sp3

Answer

sp3d2

Question 8

Which of the following alkenes has the lowest boiling point?

Accepted Answer

Ethene

Answer

Propene

Answer

1-Butene

Answer

2-Butene

Question 9

Which of the following reactions is used to synthesize alkynes?

Accepted Answer

Elimination of two equivalents of HCl from vicinal dihalides

Answer

Hydrolysis of alkyl halides

Answer

Alkylation of alkynes

Answer

Addition of HBr to alkynes

Question 10

The infrared spectrum of an alkyne shows a characteristic absorption peak at around:

Accepted Answer

2100 cm^-1

Answer

3300 cm^-1

Answer

1600 cm^-1

Answer

1000 cm^-1

Question 11

Specifically, what is an alkene?

Accepted Answer

A compound containing one or more carbon-carbon double bonds

Answer

A saturated hydrocarbon

Answer

A compound less reactive than alkanes

Answer

A compound with only single bonds between carbon atoms

Question 12

Which of the following reactions is typical of alkenes?

Accepted Answer

Addition of hydrogen

Answer

Electrophilic aromatic substitution

Answer

Nucleophilic substitution

Answer

Rearrangement

Question 13

What is the hybridization of the carbon atoms involved in the double bond of an alkene?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 14

Which of the following is NOT a defining characteristic of alkenes?

Accepted Answer

Are saturated hydrocarbons

Answer

Contain one or more carbon-carbon double bonds

Answer

Exhibit unsaturation

Answer

Can undergo addition reactions

Question 15

What type of hybridization is present in the carbon atoms of an sp2 hybridized alkene?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 16

What is the hybridization of the carbon atom involved in the triple bond of an alkyne?

Accepted Answer

sp

Answer

sp2

Answer

sp3

Answer

sp3d

Question 17

Which type of reaction is characteristic of alkenes?

Accepted Answer

Addition reactions

Answer

Substitution reactions

Answer

Elimination reactions

Answer

Redox reactions

Question 18

Determine the product formed when hydrogen reacts with ethene in the presence of a palladium catalyst.

Accepted Answer

Ethane

Answer

Ethylene

Answer

Ethane and ethylene

Answer

No reaction

Question 19

Identify the common reagent used for epoxidation of alkenes.

Accepted Answer

OsO4

Answer

KMnO4

Answer

H2SO4

Answer

NaOH

Question 20

Which spectroscopic technique is useful for identifying the presence of a carbon-carbon triple bond?

Accepted Answer

Infrared spectroscopy

Answer

Nuclear magnetic resonance spectroscopy

Answer

Mass spectrometry

Answer

Ultraviolet-visible spectroscopy

Question 21

Which of the following accurately describes the characteristic structural feature of alkenes?

Accepted Answer

Contain at least one carbon-carbon double bond

Answer

Are saturated hydrocarbons containing only single bonds

Answer

Possess a triple bond between two carbon atoms

Answer

Exhibit high reactivity due to their open-chain structure

Question 22

In the reaction of CH3-CH=CH-CH3 with water, what is the major product formed?

Accepted Answer

CH3-CH(OH)-CH2-CH3

Answer

CH3-CH2-CH(OH)-CH3

Answer

CH3-CH=CH-OH

Answer

CH3-CO-CH3

Question 23

Which hybridization accurately describes the bonding of carbon atoms in an alkyne?

Accepted Answer

sp

Answer

sp2

Answer

sp3

Answer

sp3d

Question 24

Which reaction is a characteristic property of alkenes?

Accepted Answer

Addition

Answer

Substitution

Answer

Elimination

Answer

Polymerization

Question 25

Which reagent is most selective for the addition of HBr to an alkene?

Accepted Answer

HBr/acetic acid

Answer

HBr

Answer

HBr/peroxide

Answer

Br2/CCl4

Question 26

What is the product of the catalytic hydrogenation of an alkyne?

Accepted Answer

Alkane

Answer

Alkene

Answer

Alkyl halide

Answer

Aldehyde

Question 27

Which functional group is present in the product of the hydration of an alkyne?

Accepted Answer

Alcohol

Answer

Ketone

Answer

Aldehyde

Answer

Carboxylic acid

Question 28

Which of the following is the most stable alkene?

Accepted Answer

Ethene

Answer

Propene

Answer

1-Butene

Answer

2-Butene

Question 29

What is the mechanism of the addition of HCl to an alkyne?

Accepted Answer

Electrophilic addition

Answer

Nucleophilic addition

Answer

Radical addition

Answer

Pericyclic addition

Question 30

Identify the product(s) formed when 1-butene undergoes ozonolysis, a reaction that cleaves the double bond.

Accepted Answer

Formaldehyde and acetaldehyde

Answer

Formaldehyde only

Answer

Acetaldehyde only

Answer

Acetone and formaldehyde

Question 31

Which statement accurately describes the stability of alkenes?

Accepted Answer

The stability of alkenes depends on the degree of substitution.

Answer

Alkenes are more stable than alkanes.

Answer

Alkenes are less stable than alkanes.

Answer

Alkenes are equally stable as alkanes.

Question 32

Apply IUPAC nomenclature rules to name the following alkyne: CH3-C≡C-CH(CH3)2.

Accepted Answer

2-methyl-3-hexyne

Answer

3-methyl-2-hexyne

Answer

4-methyl-2-hexyne

Answer

2-methyl-2-hexyne

Question 33

Determine the hybridization of the carbon atoms in the double bond of an alkene.

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 34

Which of the following statements about alkenes is **incorrect**?

Accepted Answer

Alkenes are generally less reactive than alkanes.

Answer

Alkenes contain one or more carbon-carbon double bonds.

Answer

Ethene is the simplest alkene.

Answer

Alkenes exhibit structural isomerism.

Question 35

What is the major product formed when ethene reacts with hydrogen in the presence of a palladium catalyst?

Accepted Answer

Ethane

Answer

Ethene

Answer

Propane

Answer

Butane

Question 36

Which of the following reactions is **unique** to alkynes?

Accepted Answer

Formation of metal acetylides

Answer

Addition of hydrogen

Answer

Addition of water

Answer

Addition of halogens

Question 37

Which of the following alkenes has the **lowest** boiling point?

Accepted Answer

Ethene

Answer

Propene

Answer

Butene

Answer

Pentene

Question 38

What is the hybridization of the carbon atoms involved in the double bond of an alkene?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 39

Which of the following alkenes **cannot** exhibit geometrical isomerism?

Accepted Answer

Ethene

Answer

Propene

Answer

2-Butene

Answer

2-Methylpropene

Question 40

What is the product formed when 1-butyne reacts with excess hydrogen in the presence of a nickel catalyst?

Accepted Answer

Butane

Answer

Butene

Answer

Pentane

Answer

Pentene

Question 41

Which reagent converts an alkyne to a cis-alkene? Explain your choice.

Accepted Answer

H₂, Lindlar's Catalyst

Answer

H₂, Ni Catalyst

Answer

NaBH<sub>4</sub>

Answer

KMnO<sub>4</sub>

Question 42

Which of the following is **not** a typical reaction of alkenes?

Accepted Answer

Nucleophilic substitution

Answer

Electrophilic addition

Answer

Free radical addition

Answer

Electrophilic addition

Question 43

Which of the following reagents can be used to convert an alkyne to a cis-alkene _selectively_?

Accepted Answer

H2/Lindlar's catalyst

Answer

Na/NH3

Answer

KMnO4

Answer

Br2

Question 44

Identify the alkene that will undergo hydroboration-oxidation to produce the most substituted alcohol.

Accepted Answer

(CH3)2C=CH2

Answer

CH3CH=CH2

Question 45

Classify the following reaction: CH3CH2CH=CH2 + KMnO4.

Accepted Answer

Oxidation

Answer

Nucleophilic addition

Question 46

Which of the following is the more stable alkene?

Accepted Answer

(CH3)2C=CH2

Answer

CH2=CH2

Question 47

Determine the product of the following reaction: CH3CH=CH2 + H2 (Pd/C).

Accepted Answer

CH3CH2CH2CH3

Answer

CH3CH=CHCH3

Question 48

Identify an example of an alkyne.

Accepted Answer

CH3C≡CH

Answer

CH3CH2CH3

Question 49

Determine the hybridization of the carbon atoms in an alkyne.

Accepted Answer

sp2

Question 50

Which reaction is characteristic of alkynes?

Accepted Answer

Nucleophilic addition

Question 51

Identify the compound that is not an isomer of 2-butene:

Accepted Answer

2-methylpropene

Answer

1-butene

Answer

(E)-2-butene

Answer

(Z)-2-butene

Question 52

Which of the following is NOT a characteristic of alkenes?

Accepted Answer

Have the general formula CnH2n+4

Answer

Contain a carbon-carbon double bond

Answer

Are unsaturated hydrocarbons

Answer

Undergo addition reactions

Question 53

Which of the following reactions is typical of alkenes?

Accepted Answer

Hydrogenation

Answer

Hydrolysis

Answer

Substitution

Answer

Esterification

Question 54

Which of the following is an example of an alkyne?

Accepted Answer

Butyne

Answer

Ethene

Answer

Propene

Answer

Benzene

Question 55

Which of the following is the most stable alkene?

Accepted Answer

Ethene

Answer

Propene

Answer

1-Butene

Answer

2-Butene

Question 56

What is the hybridization of the carbon atoms in the double bond of an alkene?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 57

Which of the following is a common application of alkynes?

Accepted Answer

As starting materials for other chemicals

Answer

As fuels

Answer

As solvents

Answer

As food additives

Question 58

Which reaction type is characteristic of alkenes?

Accepted Answer

Electrophilic addition

Answer

Nucleophilic subtraction

Answer

Radical substitution

Answer

Base-catalyzed elimination

Question 59

What is the hybridization state of the carbon atoms involved in the double bond of an alkene?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 60

Which compound is classified as an alkyne?

Accepted Answer

CH3C≡CH

Answer

CH3CH2CH=CH2

Answer

CH3CH2CH2OH

Answer

CH3COOH

Question 61

What is the hybridization of the carbon atoms involved in the triple bond of an alkyne?

Accepted Answer

sp

Answer

sp2

Answer

sp3

Answer

sp3d

Question 62

Predict the major product of the reaction between 1-pentene and Cl2

Accepted Answer

1,2-dichloropentane

Answer

1,1-dichloropentane

Answer

2,2-dichloropentane

Answer

1,1,2-trichloropentane

Question 63

Which of the following polymers is derived from an alkyne monomer?

Accepted Answer

Polyisoprene

Answer

Polyethylene

Answer

Polypropylene

Answer

Polyvinyl chloride

Question 64

Which of the following reactions is characteristic of alkenes?

Accepted Answer

Addition

Answer

Substitution

Answer

Elimination

Answer

Rearrangement