Deck 11: Alkanes

Question 1

Which type of hydrocarbons are alkanes?

A) heterocyclic
B) aromatic
C) saturated
D) unsaturated

Answer 1

C

Question 2

Which of the following is the molecular formula of heptane?

A) C₅H₁₂
B) C₆H₁₄
C) C₇H₁₆
D) C₈H₁₈

Answer 2

C

Question 3

Octane is an alkane having eight carbon atoms in its carbon chain. What is the total number of hydrogen atoms in octane?

A) 22
B) 16
C) 18
D) 20

Answer 3

C

Question 4

Which of the following compounds contains a carbon-carbon double bond?

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

Question 5

What is the name given to a -CH₂- group?

A) methane
B) methoxy
C) methylene
D) methyl

Question 6

Which of the following compounds is an alkane?

A) C₅H₁₀
B) C₆H₁₀
C) C₇H₁₈
D) C₈H₁₈

Question 7

Unbranched hydrocarbons are also called straight-chain hydrocarbons. Which of the following is true of unbranched hydrocarbons?

A) The C-C-C bond angle is 180° in unbranched hydrocarbons.
B) Each carbon atom is connected to not more than two other carbon atoms.
C) The C-C-C bond angle is 180^o in unbranched hydrocarbons and each carbon atom is connected to not more than two other carbon atoms.
D) None of these.

Question 8

Which of the following is the molecular formula of nonane?

A) C₉H₂₂
B) C₉H₂₀
C) C₉H₂₁
D) C₉H₁₈

Question 9

Which of the following represents the molecular formula of an alkane?

A) C₁₀H₃₂
B) C₁₀H₄₀
C) C₁₀H₄₂
D) C₁₀H₂₂

Question 10

Which of the following compounds contains only carbon-carbon single bonds?

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

Question 11

Which of the following compounds contain one or more benzene-like ring structures?

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

Question 12

Which of the following hydrocarbons contains the maximum number of carbon atoms?

A) butane
B) pentane
C) ethane
D) propane

Question 13

Which of the following represents the molecular formula of a noncyclic alkane?

A) C₅H₁₀
B) C₆H₁₂
C) C₄H₈
D) none of these

Question 14

Decane is an alkane having ten carbon atoms in its carbon chain. What is the total number of hydrogen atoms in decane?

A) 12
B) 24
C) 22
D) 18

Question 15

Which of the following is the molecular formula of hexane?

A) C₆H₆
B) C₆H₁₀
C) C₆H₁₄
D) C₆H₁₆

Question 16

Why are alkanes called saturated hydrocarbons?

A) because alkanes are used as solvents for most organic compounds
B) because alkanes are highly reactive organic compounds
C) because alkanes contain only carbon-carbon single bonds
D) because alkanes are found in animal fats and plant oils

Question 17

Which of the following compounds contains a carbon-carbon triple bond?

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

Question 18

Which of the following is the molecular formula of heptane?

A) C₇H₁₂
B) C₇H₁₆
C) C₇H₂₂
D) C₇H₁₄

Question 19

What is the H-C-H bond angle in a methane molecule?

A) 104°
B) 120°
C) 105.9°
D) 109.5°

Question 20

Which of the following correctly describes the relationship between butane and 2-methylpropane?

A) They have the same molecular formula.
B) They have the same chemical properties.
C) They have the same physical properties.
D) All of these are true.

Question 21

Which of the following compounds are representations of the same molecule? (i) CH₃CH₂CH₂CH₂CH₂CH<sub>3
(ii)

(iii)</sub>

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) all of these

Question 22

How many different substituent groups can be obtained by removing a hydrogen atom from butane?

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

Question 23

Hexane and 2-methylpentane are constitutional isomers. Which of the following statements is true of these isomers?

A) Hexane and 2-methylpentane have the same melting point.
B) Hexane and 2-methylpentane have the same boiling point.
C) Hexane and 2-methylpentane have the same molecular formula.
D) Hexane and 2-methylpentane have the same molecular structure.

Question 24

Which of the following is a constitutional isomer of hexane?

A) CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₃
B)
C) both CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₃ and
D) none of these

Question 25

How many constitutional isomers have the molecular formula C₆H₁₄?

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

Question 26

Which of the following is true of a hydrocarbon with a branched chain?

A) The longest chain of carbon atoms is the parent chain, and its name becomes the root name.
B) The shortest chain of carbon atoms is the parent chain, and its name becomes the root name.
C) The longest chain of carbon atoms is the parent chain, and its name becomes the root name and the shortest chain of carbon atoms is the parent chain, and its name becomes the root name.
D) None of these.

Question 27

What is the molecular formula of the following compound?

A) C₈H₂₀
B) C₈H₁₆
C) C₈H₁₇
D) C₈H₁₈

Question 28

How many different substituent groups can be obtained by removing a hydrogen atom from ethane?

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

Question 29

Which of the following are representations of the same molecule? (i) CH₃CH₂CH₂CH₂CH₂CH₂CH<sub>3
(ii)

(iii)</sub>

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of these

Question 30

Which of the following compounds are constitutional isomers? ​ ​
​

A) (i) and (ii)
B) (i) and (iii)
C) (ii) and (iii)
D) all of these

Question 31

Which of the following compounds among 2,3-dimethylpentane, 3-ethylpentane, and 3-methylhexane are constitutional isomers of heptane?

A) only 2,3-dimethylpentane and 3-ethylpentane
B) only 2,3-dimethylpentane and 3-methylhexane
C) only 3-ethylpentane and 3-methylhexane
D) all of these

Question 32

Which of the following is a constitutional isomer of butane?

A) CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₃
B)
C)
D) all of these

Question 33

How many different substituent groups can be obtained by removing a hydrogen atom from propane?

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

Question 34

How is a isobutyl group formed?

A) by removing a hydrogen atom from the first carbon of butane
B) by removing a hydrogen atom from the second carbon of butane
C) by removing a hydrogen atom from the first carbon of 2-methylpropane
D) by removing a hydrogen atom from the second carbon of 2-methylpropane

Question 35

Which of the following is a constitutional isomer of hexane?

A)
B)
C) both and

D) none of these

Question 36

Which of the following is the correct IUPAC rule for naming an alkyl group?

A) The suffix -yl is added to the name of the parent hydrocarbon.
B) The suffix -ane is replaced with the suffix -yl.
C) The suffix -ane is replaced with the suffix -anyl.
D) The suffix -yl is inserted before the suffix -ane.

Question 37

How is a butyl group formed?

A) by removing a hydrogen atom from the first carbon of butane
B) by removing a hydrogen atom from the second carbon of butane
C) by removing a hydrogen atom from the first carbon of 2-methylpropane
D) by removing a hydrogen atom from the second carbon of 2-methylpropane

Question 38

Of the given compounds, which compound is not a constitutional isomer of the other three compounds? 2,3-dimethylpentane, 3-ethylpentane, 2,2-dimethylbutane, and 3-methylhexane

A) 2,3-dimethylpentane
B) 3-methylhexane
C) 3-ethylpentane
D) 2,2-dimethylbutane

Question 39

Which of the following are constitutional isomers? (i) CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH<sub>3
(ii)

(iii)</sub>

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of these

Question 40

Which of the following are constitutional isomers? (i) CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH<sub>3
(ii)

(iii)</sub>

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of these

Question 41

What is the correct IUPAC name for the following compound?

A) 3,3-diethyl-6-methylheptane
B) isododecane
C) 3,3-dimethyl-6-ethylheptane
D) 1,1,1-triethyl-4-methylpentane

Question 42

Which of the following is a correct IUPAC name?

A) 2-ethylpropane
B) 2-ethylbutane
C) 2-ethylpentane
D) none of these

Question 43

What is the IUPAC name of the given compound?

A) 4-ethyl-4-methyloctane
B) 3-methyl-3-propylheptane
C) 2-ethyl-2-propylhexane
D) none of these

Question 44

Students were shown the structure of an alkane and were asked to write the IUPAC name of the alkane for an exam. Of the following answers that were given, which answer corresponds to the correct IUPAC name of a compound?

A) 2-ethyl-2-methylbutane
B) 2,2-dimethylbutane
C) 2,2-diethylbutane
D) none of these

Question 45

How is a sec-butyl group formed?

A) by removing a hydrogen atom from the first carbon of butane
B) by removing a hydrogen atom from the second carbon of butane
C) by removing a hydrogen atom from the first carbon of 2-methylpropane
D) by removing a hydrogen atom from the second carbon of 2-methylpropane

Question 46

Which of the following is a correct IUPAC name?

A) 1-methylpentane
B) 2-ethylpentane
C) 3-ethylpentane
D) None, they are all incorrect.

Question 47

Which of the following is the correct line-angle structure for 3-ethylheptane?

A)
B)
C)
D)

Question 48

When deriving an IUPAC name, which of the following prefixes should not be ignored during the alphabetizing of substituents?

A) iso
B) di-
C) sec-
D) All of these should be ignored.

Question 49

A student named a compound 2,2-diethylpentane. Although this name correctly represents the connectivity of the compound, it is not a valid IUPAC name. What is the correct IUPAC name of this compound?

A) 3-ethyl-3-methylhexane
B) 3-methyl-3-propylpentane
C) 2-ethyl-2-propylbutane
D) 4,4-diethylpentane

Question 50

Which of the following line-angle structures is 4-isopropyloctane?

A)
B)
C)
D)

Question 51

Pentane and 2-methylbutane have a third constitutional isomer called neopentane. What is the IUPAC name of neopentane?

A) 2,2-dimethylpropane
B) 2-methylisobutane
C) 2-ethylpropane
D) none of these

Question 52

How is a tert-butyl group formed?

A) by removing a hydrogen atom from the first carbon of butane
B) by removing a hydrogen atom from the second carbon of butane
C) by removing a hydrogen atom from the first carbon of 2-methylpropane
D) by removing a hydrogen atom from the second carbon of 2-methylpropane

Question 53

What is the correct IUPAC name for the following compound?

A) 2,2-dimethylhexane
B) 2,2-dimethylpentane
C) 1,1,1-trimethylbutane
D) 4,4,4-trimethylbutane

Question 54

What is the common name of 2-methylbutane?

A) isopentane
B) neopentane
C) 2-methylisopropane
D) none of these

Question 55

Which of the following is a correct IUPAC name?

A) 1-methylhexane
B) 2-ethylhexane
C) 3-propylhexane
D) none of these

Question 56

Which of the following is a correct IUPAC name?

A) 2-ethyl-3-methylpentane
B) 2,2-dimethylpentane
C) 2,2-diethylpentane
D) all of these

Question 57

A student named a compound 2-methyl-2-ethylbutane. Although this name correctly represents the connectivity of the compound, it is not a valid IUPAC name. What is the correct IUPAC name of this compound?

A) 2-ethyl-2-methylbutane
B) 3,3-dimethylpentane
C) 2,2-diethylpropane
D) 2,2-dimethylpentane

Question 58

What is the IUPAC name of the given compound?

A) 2-ethyl-2-methylpropane
B) 2,2-dimethylbutane
C) 3,3-dimethylbutane
D) none of these

Question 59

Which is the correct IUPAC name for the following compound?

A) 2,2-diethylpentane
B) 4-ethyl-4-methylhexane
C) 4-methyl-4-ethylhexane
D) 3-ethyl-3-methylhexane

Question 60

When deriving an IUPAC name, which of the following prefixes should be ignored during the alphabetizing of substituents?

A) di-
B) sec-
C) tri-
D) all of these

Question 61

What is the IUPAC name of the following compound?

A) 1,1-dipropylcyclohexane
B) 1-isopropyl-1-propylcyclohexane
C) isopropylpropylcyclohexane
D) 1,1-isopropylbutylcyclohexane

Question 62

What is the IUPAC name of the following compound?

A) diethylcyclopentane
B) butylcyclopentane
C) 1,1-diethylcyclopentane
D) 1,1-diethylcyclohexane

Question 63

Which of the following compounds has isohexane as the common name?

A) CH₃(CH₂)₄CH₃
B)
C) CH₃(CH₂)₂CH(CH₃)₂
D) none of these

Question 64

Which of the following is the most stable conformation of cyclohexane?

A) boat
B) chair
C) envelope
D) twist

Question 65

Why do alkanes have different conformations?

A) because they have free rotation about their C-H bonds
B) because they have free rotation about their C-C bonds
C) because they have restricted rotation about their C-H bonds
D) because they have highly reactive C-C bonds

Question 66

What is the bond angle in cyclopentane?

A) 109.5^°
B) 108.5^°
C) 90^°
D) 180^°

Question 67

Which of the following hydrocarbons is a gas?

A) methane
B) hexane
C) nonane
D) pentane

Question 68

What is the IUPAC name of the given compound?

A) 2-sec-butyl-2-propylbutane
B) 4-ethyl-3,4-dimethylheptane
C) 3,4-dimethyl-3-propylhexane
D) none of these

Question 69

Which of the following is a correct statement about the conformation given below?

A) The ethyl and methyl groups are in the axial positions.
B) All three alkyl substituents are in equatorial positions.
C) The ethyl group is in an axial position, whereas the methyl group and propyl groups are in equatorial positions.
D) The ethyl and methyl groups are in equatorial positions, whereas the propyl group is in an axial position.

Question 70

Which of the following is true of the C-H equatorial bonds in cyclohexane?

A) Each carbon atom of the ring is bonded to two hydrogen atoms at equatorial positions.
B) The C-H equatorial bonds are oriented perpendicular to the imaginary axis of the ring.
C) The C-H equatorial bonds are positioned on the same side of the ring.
D) All C-H equatorial bonds point upward.

Question 71

Which of the following is true when there is a methyl group bonded to cyclohexane?

A) The methyl group will orient itself in the axial position.
B) The methyl group will orient itself in the equatorial position.
C) The methyl group first orients itself in the equatorial position then changes to the axial position.
D) The methyl group first orients itself in the axial position then changes to the equatorial position.

Question 72

Which of the following is true of cyclobutane?

A) It is a five-membered cyclic hydrocarbon.
B) It has one carbon-carbon double bond.
C) It is a saturated cyclic hydrocarbon.
D) It is a four-membered, open-chain hydrocarbon.

Question 73

Which of the following is the most stable conformation of cyclopentane?

A) boat
B) chair
C) envelope
D) twist

Question 74

Which of the following is a correct IUPAC name?

A) 1-methyl-4-ethylcyclohexane
B) cis-1,4-dimethylcyclohexane
C) cis-1,1,2-trimethylcyclohexane
D) 1-methyl-1-ethylcyclobutane

Question 75

Which of the following is true of the different conformations of a cycloalkane?

A) They are constitutional isomers of one another.
B) They are obtained by rotation about the carbon-carbon bonds.
C) They are obtained by the formation of new carbon-carbon bonds.
D) They are equally stable.

Question 76

What is the most abundant alkane present in natural gas?

A) butane
B) propane
C) ethane
D) methane

Question 77

Which of the following is true of the C-H axial bonds in cyclohexane?

A) There are five C-H axial bonds in cyclohexane.
B) The C-H axial bonds are oriented parallel to the imaginary axis of the ring.
C) The C-H axial bonds are positioned on the same side of the ring.
D) All C-H axial bonds point downward.

Question 78

Which of the following ring sizes of cycloalkanes are found in abundance in nature?

A) 3 and 4 carbon atom rings
B) 4 and 5 carbon atom rings
C) 5 and 6 carbon atom rings
D) 6 and 7 carbon atom rings

Question 79

What is the IUPAC name of the following compound?

A) 2-propylcyclohexane
B) isopropylcyclohexane
C) 1-propylhexane
D) propylcyclohexane

Question 80

What is the IUPAC name of the given compound?

A) 2-isopropyl-2,3-dimethylpentane
B) 2-sec-butyl-2-isopropylpropane
C) 2,3,3,4-tetramethylhexane
D) none of these