Deck 12: Alkenes, Alkynes, and Aromatic Compounds

Question 1

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

A) the alkane
B) the alkene
C) the alkyne
D) none of these

Answer 1

C

Question 2

Which of the following characteristics is associated with the presence of cis-trans isomerism?

A) the presence of double bonds
B) the presence of ring systems
C) the presence of both double bonds and ring systems
D) the absence of both double bonds and ring systems

Answer 2

C

Question 3

Which of the following is true of ethylene?

A) It is not an important industrial chemical.
B) It is present in large amounts in natural gas.
C) It is formed by the catalytic hydrogenation of ethane.
D) It is produced by heating ethane to around 800-900°C.

Answer 3

D

Question 4

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

A) The alkene is always named based on the shortest carbon chain in a branched structure.
B) The position of the double bond is always given the highest possible number.
C) The position and identity of substituents determine the number associated with the position of the double bond.
D) None of these are correct.

Question 5

What is the observed H-C-C bond angle in ethylene?

A) 180°
B) 90°
C) 109.5°
D) 121.7°

Question 6

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

A) the alkane
B) the alkene
C) the alkyne
D) none of these

Question 7

Which class of compounds are not widespread in nature and have little importance in biochemistry?

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

Question 8

In alkenes, there are four groups bonded to the carbons that 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 in an alkene are the same, but the fourth group is different
D) none of these

Question 9

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

A) double bonds
B) ring systems
C) triple bonds
D) none of these

Question 10

In alkenes, there are four groups bonded to the carbons that 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 one double-bonded carbon is bonded to two identical groups and the other double-bonded carbon is bonded to two other identical groups
C) when three of the four groups are the same, but the fourth group is different
D) none of these

Question 11

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

A) The alkene is named based on the longest carbon chain that 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 determine the number associated with the position of the double bond.
D) None of these are correct.

Question 12

In which of the following hydrocarbons is the bond angle about the carbon atom approximately 120°?

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

Question 13

Which compound derived from natural gas is a starting material for the production of ethylene?

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

Question 14

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

A) The hydrogens on either side of the carbon-carbon double bond lie in different planes.
B) The carbon and hydrogen atoms lie in the same plane.
C) The carbon and hydrogen atoms bond to form a tetrahedral molecule.
D) The two carbon atoms lie in one plane, and the four hydrogen atoms lie in another plane.

Question 15

Which of the following compounds have cis-trans isomers because they lack free rotation about their carbon-carbon bonds?

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

Question 16

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) They have the same structural connectivity and the same physical properties.
D) None of these.

Question 17

Which of the following is a characteristic of 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 a hydroxyl group
D) the presence of a ring system

Question 18

Which of the following is the most common method used to manufacture ethylene?

A) the polymerization of hydrocarbons
B) the thermal cracking of hydrocarbons
C) the condensation of hydrocarbons
D) the biological degradation of hydrocarbons

Question 19

Which of the following is a characteristic of 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 cis-trans isomers
D) the presence of a ring system

Question 20

To which class of compounds do alkenes and alkynes containing only carbon and hydrogen belong?

A) halogenated compounds
B) alcoholic compounds
C) aromatic compounds
D) unsaturated compounds

Question 21

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 22

Which of the following compounds with the molecular formula C₅H₁₀ has cis and trans isomers?

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

Question 23

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 24

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) 4,5-dimethyl-4-hexene

Question 25

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) 3-methyl-1-butene
D) 1,2-dimethylcyclopropane

Question 26

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 27

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

A) The alkene is always named based on the shortest carbon chain in a branched structure.
B) The position of the double bond is always given the lowest possible number.
C) The position and identity of substituents determine the number associated with the position of the double bond.
D) None of these are correct.

Question 28

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

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

Question 29

Which of the following is true of ethylene and acetylene?

A) Ethylene contains more carbon atoms than acetylene does.
B) Ethylene has a carbon-carbon double bond, and acetylene has a carbon-carbon triple bond.
C) Ethylene and acetylene are the IUPAC names of two-carbon compounds.
D) Ethylene and acetylene belong to a single class of compounds called alkenes.

Question 30

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) none of these

Question 31

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 32

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 33

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 34

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 35

Which of the following compounds with 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, they all have cis isomers.

Question 36

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 37

Which of the following compounds with 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) cyclohexane

Question 38

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

A)
B)
C)
D)

Question 39

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 40

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 41

What is the configuration of each of the given alkenes?

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

Question 42

What is the IUPAC name of the following molecule?

A) 2,2-diethylcyclopentene
B) 1,1-dimethylcyclopentene
C) 1,2-dimethylcyclopentene
D) 1,3-dimethylcyclopentene

Question 43

Including cis-trans isomers, how many stereoisomers are possible for an alkene that has the molecular formula C₄H₈?

A) 2
B) 6
C) 4
D) 5

Question 44

Which of the following attractive forces are found among the molecules of alkenes and alkynes?

A) electromagnetic forces
B) London dispersion forces
C) nuclear forces
D) strong ionic forces

Question 45

In which of the following compounds is free rotation about all bonds possible?

A) 2-butene
B) cyclobutane
C) butane
D) butyne

Question 46

Which of the following reagents is used to convert cyclohexene to 1-iodo-cyclohexane?

A) hydrogen peroxide
B) iodine in dichloromethane
C) hydrogen iodide
D) nitric acid in sulfuric acid

Question 47

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) trans-3,4-dimethylcyclopentene

Question 48

Which of the following is true of the noncyclic 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 that alternate as cis, trans, cis, and trans.
D) It contains 4 double bonds that alternate as trans, cis, trans, and cis.

Question 49

Which of the following is true of 2-methyl-1,3-butadiene?

A) It contains two double bonds adjacent to each other.
B) It contains four cis-trans isomers.
C) It does not exhibit cis-trans isomerism.
D) It contains a C-C-C bond angle equal to 109°.

Question 50

Which of the following strategies is used while naming a cycloalkene?

A) The substituents are numbered first, and the numbering is continued in the direction where the double bond gets the lowest possible number.
B) The cyclic ring is broken down at one of the positions of the double bond, and the numbering is done as with the alkenes.
C) The double bond is numbered 1 and 2 in the direction where a substituent gets the lowest possible number.
D) The double bond is numbered 1 and 2 in the direction where a substituent gets the highest possible number.

Question 51

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

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

Question 52

Identify the similarity between the following two molecules.

A) Both are cis isomers.
B) Both have the same boiling point.
C) Both have the same melting point.
D) Both undergo hydrogenation reactions.

Question 53

Including cis-trans isomers, how many different stereoisomers are possible for an alkene that has the molecular formula C₅H₁₀?

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

Question 54

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

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

Question 55

Which of the following molecules with the molecular formula C₅H₈ has stereoisomers?

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

Question 56

Why is the C-C-C bond angle in propene 124.7° instead of the predicted angle of 120°?

A) because of the presence of a tetrahedral structure
B) because of the presence of two trans methyl groups
C) because of the interaction between the methyl group and the double-bonded carbon
D) because of free rotation about the double-bonded carbons

Question 57

Which of the following is not a correct IUPAC name?

A) 3-methylcyclopentene
B) 4-methylcyclopentene
C) 5-methylcyclopentene
D) 1-methylcyclopentene

Question 58

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

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

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

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

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

Question 61

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

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

Question 62

Which of the following statements is true of an electrophile?

A) It is an electron-rich species.
B) It reacts with an electron-donor species to form a new bond.
C) It attacks an electron-deficient species.
D) It is a stable species and does not undergo any reaction.

Question 63

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

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

Question 64

Identify the order of reactions in the mechanism of an addition reaction between HCl and 2-butene.

Question 65

Which of the following products is formed when the given substance reacts with hydrogen?

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

Question 66

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

A) hydrogenation
B) hydrobromination
C) both hydrogenation and hydrobromination
D) neither hydrogenation nor hydrobromiantion

Question 67

What happens when the following substance reacts with water in the presence of concentrated sulfuric acid?

A) An alkyne is produced.
B) An alcohol is produced.
C) The substance is converted to its cis isomer.
D) The substance is converted to its trans isomer.

Question 68

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

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

Question 69

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

A)
B)
C)
D)

Question 70

Which of the following statements is true of 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 71

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

A) C₄H₁₀
B)
C)
D) C₂H₂
E) none of these

Question 72

Examine the following reaction. Which of the following describes this reaction?

A) It involves a secondary carbocation.
B) A represents the nucleophile.
C) B represents the electrophile.
D) It involves the formation of a new carbon-carbon bond.
E) All of these are correct.

Question 73

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) an alkyne
B) an alcohol
C) an aldehyde
D) a carboxylic acid

Question 74

Consider the given molecule. Which of the following is a characteristic of the given molecule?

A) It is an alkene.
B) It is a cis isomer.
C) It is the stereoisomer of the following molecule.
D) All of these are characteristics of this compound.

Question 75

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 76

Which of the following is true of the given compound?

A) It is the simplest alkene.
B) It is an alkyne.
C) It has at least one bond angle close to 120°.
D) It has free rotation about all its bonds.

Question 77

addition of a proton to 2-butene

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

Question 78

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

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

Question 79

Propene reacts with hydrogen chloride to form mostly 2-chloropropane. This reaction does not lead to the formation of 1-chloropropane. Why?

A) because it is a substitution reaction
B) because it is a hydrogenation reaction
C) because it is a regioselective reaction
D) because it is a hydration reaction

Question 80

reaction of a chloride ion with an intermediate to form 2-chlorobutane