Alkenes and Alkynes: Structure, Properties, and Reactions

Question 1

What is the product of the oxidative cleavage of an alkene with ozone followed by reduction with zinc dust and water?

Accepted Answer

Alcohol

Answer

Ketone

Answer

Aldehyde

Answer

Carboxylic acid

Question 2

How do catalysts facilitate hydrogenation reactions of alkenes and alkynes?

Accepted Answer

Catalysts lower the activation energy, providing an alternative reaction pathway.

Answer

Catalysts are consumed during the reaction.

Answer

Catalysts alter the reaction products.

Question 3

According to Markovnikov's rule, which reagent will add to an alkene to produce a more substituted carbocation?

Accepted Answer

HBr

Answer

H2O

Answer

CH3OH

Answer

KMnO4

Question 4

Which of the following is considered a nucleophile?

Accepted Answer

OH-

Answer

H+

Answer

Cl-

Answer

CH3Br

Question 5

Name the reaction that occurs between an alkene and a hydrogen halide.

Accepted Answer

Addition reaction

Answer

Substitution reaction

Answer

Elimination reaction

Answer

Polymerization reaction

Question 6

Identify the most reactive alkene in electrophilic addition reactions from the given options.

Accepted Answer

2-Methylpropene

Answer

Ethene

Answer

Propene

Answer

1-Butene

Question 7

Identify the alkyne from the following compounds.

Accepted Answer

CH3C≡CH

Answer

CH3CH=CH2

Answer

CH3CH2CH2OH

Answer

CH3COOH

Question 8

Identify the alkane in the following list:

Accepted Answer

Propane

Answer

Ethene

Answer

Butyne

Answer

Pentene

Question 9

Explore the diverse applications of alkenes and alkynes in both environmental and industrial settings.

Accepted Answer

Biodegradable plastics and solvents (environmental)

Accepted Answer

Monomers for polymers and fuels (industrial)

Accepted Answer

Applications in both environmental and industrial contexts

Answer

Limited applications in both environmental and industrial contexts

Question 10

Alkenes and alkynes are important industrial chemicals. Which of these is NOT a common use for them?

Accepted Answer

Generating electricity

Answer

Making plastics

Answer

Making synthetic rubber

Answer

Use as fuel additives

Question 11

Which of the following is an example of a cyclic alkene?

Accepted Answer

Cyclopentene

Answer

Cyclohexane

Answer

Propene

Answer

Butene

Question 12

Which of the following is the major product of the hydroboration-oxidation reaction of CH3CH=CH2?

Accepted Answer

CH3CH2CH2OH

Answer

CH3CHO

Answer

CH2=CHCH2OH

Answer

CH3CHOHCH3

Question 13

Which of the following is NOT a structural isomer of butene?

Accepted Answer

1-chlorobutane

Answer

2-butene

Answer

1-butene

Answer

isobutene

Question 14

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

Accepted Answer

sp²

Answer

sp³

Answer

sp³d

Answer

sp

Question 15

Which of the following reactions does NOT involve an alkene?

Accepted Answer

Nucleophilic substitution

Answer

Electrophilic addition

Answer

Hydrogenation

Answer

Polymerization

Question 16

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

Accepted Answer

sp

Answer

sp²

Answer

sp³d

Answer

sp³

Question 17

Which of the following reactions is characteristic of alkynes?

Accepted Answer

Addition of hydrogen cyanide (HCN)

Answer

Nucleophilic substitution

Answer

Esterification

Answer

Electrophilic addition

Question 18

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

Accepted Answer

They are **soluble** in water.

Answer

They can undergo hydrogenation reactions.

Answer

They contain one or more carbon-carbon double bonds.

Answer

They are generally non-polar.

Question 19

What is the primary product formed when hydrogen gas (H₂) is added to an alkyne?

Accepted Answer

An alkane

Answer

A cycloalkane

Answer

An alkene

Answer

An alcohol

Question 20

What is the hybridization of each carbon atom forming the double bond of an alkene?

Accepted Answer

sp²

Answer

sp³d

Answer

sp³

Answer

sp

Question 21

Which of the following compounds is classified as an alkyne?

Accepted Answer

HC≡CH

Answer

CH3CH2CH3

Answer

CH3CH2OH

Answer

CH3CH=CH2

Question 22

Which of the following reactions is NOT characteristic of alkynes?

Accepted Answer

Substitution reactions

Answer

Oxidation reactions

Answer

Addition reactions

Answer

Polymerization reactions

Question 23

Which statement accurately describes the structure of alkenes?

Accepted Answer

Alkenes contain a carbon-carbon double bond.

Answer

Alkenes possess a carbon-carbon triple bond.

Answer

Alkenes consist solely of single bonds.

Question 24

Determine the general formula for alkynes.

Accepted Answer

CnH2n-2

Answer

CnH2n

Answer

CnH2n+2

Answer

CnHn

Question 25

Which type of reaction is characteristic of alkenes?

Accepted Answer

Addition reactions

Answer

Substitution reactions

Answer

Elimination reactions

Answer

Redox reactions

Question 26

Identify the product of the addition reaction between ethene (C₂H₄) and bromine (Br₂).

Accepted Answer

1,2-dibromoethane (CH₂Br-CH₂Br)

Answer

Ethane (C₂H₆)

Answer

Bromoethane (CH₃-CH₂Br)

Question 27

Name the alkene with the molecular formula C₄H₈.

Accepted Answer

Butene

Answer

Hexene

Answer

Pentene

Answer

Propene

Question 28

Which reagent is commonly used to test for the presence of a carbon-carbon double bond?

Accepted Answer

Bromine water

Answer

Sodium hydroxide solution

Answer

Dilute hydrochloric acid

Question 29

What is the product formed when hydrogen gas (H₂) is added to an alkene?

Accepted Answer

An alkane

Answer

An alkyne

Answer

Another alkene

Answer

An alcohol

Question 30

Identify the primary product formed when ethyne (C₂H₂) reacts with water in the presence of a catalyst.

Accepted Answer

Ethanal (CH₃CHO)

Answer

Ethanoic acid (CH₃COOH)

Answer

Ethanol (CH₃CH₂OH)

Question 31

Explain the difference in reactivity between alkenes and alkanes.

Accepted Answer

Alkenes are more reactive than alkanes due to the presence of a carbon-carbon double bond, which is electron-rich and susceptible to attack by electrophiles.

Answer

Alkanes are more reactive than alkenes because they contain stronger carbon-carbon single bonds.

Question 32

What is the major product formed when ethene reacts with bromine water?

Accepted Answer

1,2-dibromoethane

Answer

Ethanol

Answer

Bromoethane

Answer

Ethane

Question 33

Which of the following is a characteristic of alkynes?

Accepted Answer

They contain a carbon-carbon triple bond.

Answer

They are generally more reactive than alkanes but less reactive than alkenes.

Answer

They are saturated hydrocarbons.

Answer

They undergo addition reactions with halogens to form alkyl halides.

Question 34

The reaction of an alkene with hydrogen gas in the presence of a nickel catalyst is an example of which type of reaction?

Accepted Answer

Hydrogenation

Answer

Halogenation

Answer

Oxidation

Answer

Dehydration

Question 35

The addition of hydrogen bromide to propene in the presence of peroxides will preferentially form which product?

Accepted Answer

1-bromopropane

Answer

2-bromopropane

Answer

Propane

Answer

1,2-dibromopropane

Question 36

Which of the following statements correctly describes the geometry around the carbon-carbon triple bond in an alkyne?

Accepted Answer

The triple bond is linear, with the two carbon atoms and the atoms bonded to them lying in a straight line.

Answer

The triple bond is tetrahedral, with the two carbon atoms and the atoms bonded to them forming a tetrahedral shape.

Question 37

Which of the following statements accurately describes the difference between alkenes and alkynes?

Accepted Answer

Alkenes have one carbon-carbon double bond, while alkynes have one carbon-carbon triple bond.

Answer

Alkenes are saturated hydrocarbons, while alkynes are unsaturated hydrocarbons.

Answer

Alkenes are more reactive than alkynes due to the presence of a double bond.

Question 38

The addition of bromine (Br2) to an alkene results in the formation of which type of product?

Accepted Answer

Dibromoalkane

Answer

Bromoalkane

Answer

Alkyl bromide

Answer

Alkane

Question 39

What is the major product of the reaction between propene and hydrogen gas (H2) in the presence of a nickel catalyst?

Accepted Answer

Propane

Answer

Propan-2-ol

Answer

Propan-1-ol

Answer

Propyne

Question 40

The reaction of an alkyne with a strong base, such as sodium amide (NaNH2), results in the formation of which type of compound?

Accepted Answer

Acetylide ion

Answer

Alkyl halide

Answer

Ketone

Answer

Aldehyde

Question 41

What is the primary function of a catalyst in the hydrogenation of an alkene or alkyne?

Accepted Answer

To lower the activation energy of the reaction.

Answer

To increase the concentration of reactants.

Answer

To provide the necessary heat for the reaction.

Answer

To change the equilibrium position of the reaction.

Question 42

Which of the following compounds would be classified as an alkene?

Accepted Answer

CH3CH=CHCH3

Answer

CH3CH2CH2CH3

Answer

CH3CH2CH2OH

Answer

CH3C≡CCH3

Question 43

The reaction of an alkyne with water in the presence of a mercury catalyst produces which type of compound?

Accepted Answer

Ketone or aldehyde

Answer

Carboxylic acid

Answer

Ether

Answer

Alcohol