Deck 12: Alkenes and Alkynes

Question 1

In alkenes there are four groups bonded to the carbons which constitute the carbon-carbon double bond. Which of the following situations produces cis-trans isomerism?

A) when all four groups are the same
B) when the two groups on one atom are the same, but the two groups on the other atom are different from each other and also different from the groups on the first atom
C) when three of the four groups are the same, but the fourth group is different
D) none of these results in the existence of cis-trans isomerism

Answer 1

D

Question 2

Which of the following is true of cis and trans isomers?

A) they have the same structural connectivity
B) they have the same physical properties
C) both a and b
D) neither a nor b

Answer 2

A

Question 3

Which of the following is true in the IUPAC system for naming alkenes?

A) The alkene is always named based on the longest carbon chain.
B) The position of the double bond is always given the highest possible number.
C) The position and identity of substituents determines the number associated with the position of the double bond.
D) None of the above is correct.

Answer 3

D

Question 4

Given an alkane, an alkene, and an alkyne, each of which contains two carbon atoms, which compound will contain most hydrogen atoms?

A) the alkane
B) the alkene
C) the alkyne
D) None, they all contain the same number of hydrogen atoms.

Question 5

In alkenes there are four groups bonded to the carbons which constitute the carbon-carbon double bond. Which of the following situations produces cis-trans isomerism?

A) when all four groups are the same
B) when the two groups bonded to each carbon atom are different from one another
C) when three of the four groups are the same, but the fourth group is different
D) None of these results in the existence of cis-trans isomerism.

Question 6

Given an alkane, an alkene, and an alkyne, each of which contains two carbon atoms, which compound will contain the fewest hydrogen atoms?

A) the alkane
B) the alkene
C) the alkyne
D) None, they all contain the same number of hydrogen atoms.

Question 7

Which of the following is the characteristic feature of all alkenes?

A) the presence of one or more carbon-carbon double bonds
B) the presence of one or more carbon-carbon triple bonds
C) the presence of at least one carbon-carbon double bond, and at least one carbon-carbon triple bond
D) the presence of a ring system

Question 8

Which of the following is true in the IUPAC system for naming alkenes?

A) The alkene is named based on the longest carbon chain which contains the double bond.
B) The position of the double bond is always given the highest possible number.
C) The position and identity of substituents determines the number associated with the position of the double bond.
D) None of the above is correct.

Question 9

Which of the following is true of ethylene?

A) It is not a very important industrial chemical.
B) It is present in large amounts in natural gas.
C) Its most important use is as a fuel.
D) The vast majority of ethylene is produced by thermal cracking.

Question 10

Given a non-cyclic alkane, a non-cyclic alkene, and a non-cyclic alkyne, each of which contains six carbon atoms, which compound will contain the fewest hydrogen atoms?

A) the alkane
B) the alkene
C) the alkyne
D) It is not possible to tell, without knowing how many double and/or triple bonds are present in the unsaturated compounds.

Question 11

Which of the following structural features is never associated with cis-trans isomerism?

A) double bonds
B) ring systems
C) triple bonds
D) None, they are all associated with cis-trans isomerism.

Question 12

For which class of compounds does the lack of free rotation around carbon-carbon bonds result in the existence of cis-trans isomerism?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Question 13

Cis-trans isomerism is associated with the presence of which of the following?

A) double bonds
B) ring systems
C) both a and b
D) neither a nor b

Question 14

Which class of compounds is not widespread in nature, and has little importance in biochemistry?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Question 15

Which of the following is true of the six atoms of ethylene?

A) Four atoms lie in the same plane, but two atoms are not in this plane.
B) All six atoms lie in the same plane.
C) The carbon atoms have a tetrahedral geometry so the C−C−H angles are approximately 109°.
D) none of the above

Question 16

Which of the following compounds is a natural ripening agent for fruits?

A) ethane
B) ethylene
C) acetylene
D) none of these

Question 17

Which of the following is the starting material derived from natural gas that is used for the production of ethylene?

A) acetylene
B) benzene
C) ethane
D) methane

Question 18

Which of the following is the characteristic feature of all alkynes?

A) the presence of one or more carbon-carbon double bonds
B) the presence of one or more carbon-carbon triple bonds
C) the presence of at least one carbon-carbon double bond, and at least one carbon-carbon triple bond
D) the presence of a ring system

Question 19

Which organic compound is produced in the largest amount by the chemical industry?

A) acetylene
B) benzene
C) ethane
D) ethylene

Question 20

A bond angle of approximately 120° is associated with the carbons in which functional group?

A) alkanes
B) alkenes
C) alkynes
D) none of these

Question 21

Which of the following compounds, all of which have the molecular formula C₆H₁₂, has cis and trans isomers?

A) 2-methyl-1-pentene
B) 2-methyl-2-pentene
C) 3-methyl-2-pentene
D) They all have cis-trans isomers.

Question 22

Which of the following is not a correct IUPAC name for an alkene?

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

Question 23

A student wanted to use the branched groups, isobutyl, sec-butyl, and tert-butyl when naming alkenes, but was told not to. What is the correct IUPAC name for the compound the student called isobutylethene?

A) 4-methyl-1-pentene
B) 3-methyl-1-pentene
C) 3,3-dimethyl-1-butene
D) none of these

Question 24

Cis-trans isomers do not exist for which of the following compounds, all of which have the molecular formula C₃H₄Br₂?

A) 1,1-dibromopropene
B) 1,2-dibromopropene
C) 1,3-dibromopropene
D) They do not exist for any of these three molecules.

Question 25

Which of the following, all of which have the molecular formula C₅H₁₀, has cis and trans isomers?

A) 2-methyl-1-butene
B) 2-methyl-2-butene
C) 2-pentene
D) none of them

Question 26

Which of the following compounds, all of which have the molecular formula C₆H₁₂, does not have cis and trans isomers?

A) 4-methyl-2-pentene
B) 2-methyl-1-pentene
C) 3-methyl-2-pentene
D) None of them, they all have cis-trans isomers.

Question 27

A student named a particular compound 2-propyl-1-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound?

A) 2-propyl-1-butene
B) 2-ethyl-1-pentene
C) 3-methyl-2-pentene
D) none of these

Question 28

Which of the following structures corresponds to cis-3-methyl-2-hexene?

A) ​

B) ​

C) ​

D) ​

Question 29

Which of the following is true of the common names of low molecular weight alkenes and alkynes?

A) The common names of all alkenes end in −ene, and those of alkynes end in −yne.
B) The common names of all alkenes and all alkynes end in −ene.
C) The common names of all alkenes and all alkynes end in −yne.
D) None of the above is correct.

Question 30

A student wanted to use the branched groups, isobutyl, sec-butyl, and tert-butyl when naming alkenes, but was told not to. What is the correct IUPAC name for the compound the student called sec-butylethene?

A) 4-methyl-1-pentene
B) 3-methyl-1-pentene
C) 3,3-dimethyl-1-butene
D) none of these

Question 31

Which of the following is not a correct IUPAC name for an alkene?

A) 2-methyl-1-butene
B) 2-methyl-2-butene
C) 2-methyl-3-butene
D) None, these are all correct IUPAC names.

Question 32

Cis-trans isomers exist for which of the following molecules, all of which have the molecular formula C₃H₅Br?

A) 1-bromopropene
B) 2-bromopropene
C) 3-bromopropene
D) none of these

Question 33

What is the correct IUPAC name for the following compound?

A) 2,2-dimethyl-4-pentene
B) 4,4-dimethyl-2-pentene
C) 4,4-dimethyl-1-pentene
D) isoheptene

Question 34

What is the correct IUPAC name for the following compound?

A) 2-methyl-3-propyl-2-butene
B) 1,1,2-trimethyl-1-pentene
C) 2,3-dimethyl-2-hexene
D) none of these

Question 35

Cis-trans isomers exist for which of the following molecules, all of which have the molecular formula C₅H₁₀?

A) 1-pentene
B) 2-methyl-1-butene
C) 2-methyl-2-butene
D) 1,2-dimethylcyclopropane

Question 36

Which of the following is true in the IUPAC system for naming alkenes?

A) The alkene is always named based on the longest carbon chain.
B) The position of the double bond is always given the lowest possible number.
C) The position and identity of substituents determines the number associated with the position of the double bond.
D) None of the above is correct.

Question 37

What is the correct IUPAC name for the following compound?

A) trans-3-propyl-3-hexene
B) cis-3-propyl-3-hexene
C) trans-4-ethyl-3-heptene
D) cis-4-ethyl-3-heptene

Question 38

What is the name of the lightest hydrocarbon which has cis and trans isomers?

A) 1-butene
B) 2-butene
C) 1,2-dimethylcyclopropane
D) propene

Question 39

Which of the following is not a correct IUPAC name for an alkene?

A) 2-methyl-1-butene
B) 2-methyl-2-butene
C) 3-methyl-1-butene
D) None, these are all correct IUPAC names.

Question 40

A student named a particular compound 2-ethyl-3-methyl-2-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound?

A) 2-ethyl-3-methyl-2-butene
B) 3,4-dimethyl-3-pentene
C) 2,3-dimethyl-2-pentene
D) 2,3-dimethyl-1-pentene

Question 41

How many stereoisomers are possible for 1,4,7-octatriene?

A) 2
B) 4
C) 8
D) 16

Question 42

Including cis-trans isomers, how many different alkenes have the molecular formula C₅H₁₀?

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

Question 43

Of the following alkenes, all of which have the molecular formula C₅H₁₀, which would you expect to have the highest boiling point?

A) 4-methyl-1-pentene
B) 4-methyl-2-pentene
C) 2,3-dimethyl-2-butene
D) 2-hexene

Question 44

How many stereoisomers are possible for 1,4,6-octatriene?

A) 2
B) 4
C) 8
D) 16

Question 45

Which of the following is true of the non-cyclic portion of vitamin A?

A) It contains 4 double bonds, all in the cis configuration.
B) It contains 4 double bonds, all in the trans configuration.
C) It contains 4 double bonds, which alternate cis, trans, cis, trans.
D) None of the above is true.

Question 46

How many stereoisomers are possible for 2,4,6-nonatriene?

A) 2
B) 4
C) 8
D) 16

Question 47

Which of the following occurs when rhodopsin absorbs light?

A) The less stable 11,12-cis isomer is converted to the more stable trans isomer.
B) The less stable 11,12-trans isomer is converted to the more stable cis isomer.
C) The more stable 11,12-cis isomer is converted to the less stable trans isomer.
D) The more stable 11,12-trans isomer is converted to the less stable cis isomer.

Question 48

How many cycloalkenes have the molecular formula C₅H₈?

A) 7
B) 8
C) 9
D) 10

Question 49

How many stereoisomers are possible for 2,4-heptadiene?

A) 2
B) 4
C) 7
D) 8

Question 50

Which of the following is not a correct IUPAC name?

A) cis-2,3-dimethylcyclopentene
B) cis-3,4-dimethylcyclopentene
C) cis-3,5-dimethylcyclopentene
D) None, they are all correct.

Question 51

How many cycloalkenes have the molecular formula C₄H₆?

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

Question 52

Stereoisomers exist for which of the following molecules, all of which have the molecular formula C₅H₈?

A) 1,3-pentadiene
B) 1,4-pentadiene
C) 2-methyl-1,3-butadiene
D) all of them

Question 53

How many stereoisomers are possible for 1,4-heptadiene?

A) 2
B) 4
C) 7
D) 8

Question 54

Which of the following alkenes, all of which have the molecular formula C₅H₁₀, would you expect to have the lowest boiling point?

A) 4-methyl-1-pentene
B) 4-methyl-2-pentene
C) 2,3-dimethyl-2-butene
D) 2-hexene

Question 55

What is the configuration of each of the alkenes shown below?

A) (i) cis (ii) cis
B) (i) trans (ii) trans
C) (i) cis (ii) trans
D) (i) trans (ii) cis

Question 56

Which of the following is not a correct IUPAC name?

A) 3-methylcyclopentene
B) 4-methylcyclopentene
C) 5-methylcyclopentene
D) None, they are all correct.

Question 57

Including cis-trans isomers, how many different alkenes have the molecular formula C₄H₈?

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

Question 58

Based on your knowledge of the properties of the analogous alkanes, which of the following is the lightest alkene that you would expect to be a liquid at room temperature?

A) propene
B) 1-pentene
C) 1-heptene
D) 1-nonene

Question 59

Which of the following is a correct IUPAC name?

A) 4-ethyl-1-methylcyclohexene
B) 5-ethyl-2-methylcyclohexene
C) 1-methyl-4-ethylcyclohexene
D) 5-methyl-2-ethylcyclohexene

Question 60

Cis-trans isomers exist for which of the following?

A) 1,2-dimethylcyclopentene
B) 2,3-dimethylcyclopentene
C) 3,5-dimethylcyclopentene
D) All of them exist.

Question 61

Markovnikov's rule is useful in predicting the outcome for which of the following addition reactions of unsymmetrical alkenes?

A) hydration
B) bromination
C) both a and b
D) neither a nor b

Question 62

Examine the following reaction. A B C Which of the following describes this reaction?

A) Involves a secondary carbocation.
B) A represents the nucleophile.
C) B represents the electrophile.
D) Produces a new carbon to carbon bond.
E) All of the above except d are correct.

Question 63

When the following substance reacts with water in the presence of an acid, which of the following describes the reaction?

A) Two products are produced.
B) The product is an alcohol.
C) both a and b
D) neither a nor b

Question 64

Consider the molecule represented below. Which of the following is a characteristic of the substance represented here?

A) alkene
B) cis isomer
C) melting point different than
D) All of these are characteristic of this compound.

Question 65

Consider the alkyne counterpart of the following compound. Which of the following would characterize this alkyne?

A) C₃H₆
B) CH₃C CH
C)
D) both a and b
E) a, b and c

Question 66

Which of the following statements is true about the solubility of alkenes?

A) All alkenes are soluble in water.
B) Long chain alkenes are soluble in water, but short chain alkenes are insoluble.
C) Long chain alkenes are insoluble in water, but short chain alkenes are soluble.
D) All alkenes are soluble in alkanes.

Question 67

Which of the following correctly characterizes the compound represented below?

A) trans isomer
B) alkyne
C) at least one 120° bond angle
D) free rotation around all bonds

Question 68

Which of the following curved arrows correctly describes the first step of the reaction of propene with a hydrogen halide?

A)
B)
C)
D) None of these are correct.

Question 69

Which of the following reactions involves the addition of different groups to the two ends of a double bond?

A) bromination
B) hydrogenation
C) both a and b
D) neither a nor b

Question 70

Markovnikov's rule is not useful for predicting the outcome of the reaction of hydrogen chloride with which of the following alkenes?

A) 1-butene
B) 2-butene
C) 2-methylpropene
D) 1-pentene

Question 71

Which of the following reactions involves the addition of two equivalent groups to the two ends of a double bond?

A) bromination
B) hydrogenation
C) both a and b
D) neither a nor b

Question 72

Consider the substance represented by the following model. The physical properties of this substance would most closely represent the corresponding member of which functional group class?

A) alkyne
B) alcohol
C) aldehyde
D) carboxylic acid

Question 73

Which of the following curved arrows correctly describes the second step in the reaction of propene with hydrogen bromide?

A)
B)
C)
D)

Question 74

Markovnikov's rule is useful to predict the outcome of the reaction of hydrogen chloride with which of the following alkenes?

A) 1-butene
B) 2-butene
C) both a and b
D) neither a nor b

Question 75

Which of the following reactions involves the addition of different groups to the two ends of a double bond?

A) hydration
B) hydrogenation
C) both a and b
D) neither a nor b

Question 76

Which of the following reactions involves the addition of different groups to the two ends of a double bond?

A) hydrogenation
B) hydrobromination
C) both a and b
D) neither a nor b

Question 77

Which of the following is the most characteristic reaction of alkenes?

A) addition
B) oxidation
C) reduction
D) substitution

Question 78

Which of the following reactions involves the addition of two equivalent groups to the two ends of a double bond?

A) hydration
B) hydrogenation
C) both a and b
D) neither a nor b

Question 79

What is the product of the reaction of the substance given below with hydrogen?

A) butyne
B) cis-butane
C) trans-butene
D) butane

Question 80

Which of the following reactions involves the addition of two equivalent groups to the two ends of a double bond?

A) hydrogenation
B) hydrobromination
C) both a and b
D) neither a nor b