Deck 5: Stereochemistry

Question 1

Which of the following statements is true?

A)Enantiomers are mirror images that are not superimposable.
B)A molecule that is superimposable on its mirror image is chiral.
C)A chiral molecule usually contains a plane of symmetry.
D)An achiral molecule does not contain a plane of symmetry.

Answer 1

Enantiomers are mirror images that are not superimposable.

Question 2

Which of the following molecules are chiral?

A)II,III
B)I,II
C)I,IV
D)III,IV

Answer 2

II,III

Question 3

Which of the following statements is true?

A)Achiral molecules usually contain a plane of symmetry.
B)With one tetrahedral stereogenic center,a molecule may or may not be chiral.
C)With two or more stereogenic centers,a molecule is always chiral.
D)Chiral molecules usually contain a plane of symmetry.

Answer 3

Achiral molecules usually contain a plane of symmetry.

Question 4

Which of the following statements is not true?

A)A molecule that is superimposable on its mirror image is said to achiral.
B)A molecule that is not superimposable on its mirror image is said to be chiral.
C)A molecule that is superimposable on its mirror image is said to be chiral.
D)A carbon atom bonded to four different groups is a stereogenic center.

Question 5

Which of the following molecules are achiral?

A)II,III
B)I,II
C)I,IV
D)III,IV

Question 6

Which of the following molecules are chiral? I.2-Chlorobutane
II)3-Bromopentane
III)1-Bromo-2-methylpropene
IV)2-Bromo-3-methylbutane

A)I,II
B)I,IV
C)II,III
D)III,IV

Question 7

What is the main carbohydrate in the seeds and roots of plants?

A)Starch
B)Glucose
C)Cellulose
D)Glycogen

Question 8

What is the relationship between the following two compounds?

A)Stereoisomers
B)Constitutional isomers
C)Identical
D)Not isomers,different compounds

Question 9

Which of the following statements about stereoisomers is not true?

A)Stereoisomers have identical IUPAC names except for a prefix like cis or trans.
B)Stereoisomers differ in configuration.
C)Stereoisomers always have the same functional groups.
D)Stereoisomers differ only in their structural formula.

Question 10

What is the relationship between the following two compounds?

A)Constitutional isomers
B)Identical
C)Stereoisomers
D)Not isomers,different compounds

Question 11

What is the relationship between the following two compounds?

A)Constitutional isomers
B)Stereoisomers
C)Identical
D)Not isomers,different compounds

Question 12

How many stereogenic centers are present in ephedrine,a bronchodilator and decongestant?

A)0
B)1
C)2
D)3

Question 13

Which of the following statements about constitutional isomers is not true?

A)They have different IUPAC names.
B)They always have the same functional groups.
C)They have different physical properties.
D)They have different chemical properties.

Question 14

What is the relationship between the following two compounds?

A)Constitutional isomers
B)Identical
C)Stereoisomers
D)Not isomers,different compounds

Question 15

Which of the following molecules are chiral? I.cis-1,3-Dibromocyclohexane
II)1-Bromo-1-methylcyclohexane
III)trans-1-Bromo-3-methylcyclohexane
IV)cis-1-Bromo-3-methylcyclohexane

A)I,II
B)II,III
C)I,IV
D)III,IV

Question 16

Which of the following statements about starch and cellulose is true?

A)Starch and cellulose are not stereoisomers.
B)In cellulose,the O atom joins two rings using one equatorial and one axial bond.
C)In starch,the O atom joins two rings using two equatorial bonds.
D)In cellulose,the O atom joins two rings using two equatorial bonds.

Question 17

Which of the following is the definition of chirality?

A)The existence of a molecule with a mirror image.
B)The existence of a molecule with a carbon atom that has four different substituents.
C)The existence of a molecule that is superimposable on its mirror image.
D)The existence of a molecule that is not superimposable on its mirror image.

Question 18

Which of the following molecules has a plane of symmetry?

A)I
B)II
C)III
D)IV

Question 19

Which of the following statements is true?

A)The presence of a plane of symmetry makes a molecule chiral.
B)An achiral molecule must have one or more stereogenic centers.
C)All molecules that have stereogenic centers are chiral.
D)Stereoisomers that are not superimposable on their mirror image are enantiomers.

Question 20

Which of the following is the correct definition for a pair of enantiomers?

A)A pair of stereoisomers that have a plane of symmetry.
B)A pair of stereoisomers that are not mirror images of each other.
C)A pair of stereoisomers that are not superimposable mirror images of each other.
D)A pair of stereoisomers that are superimposable mirror images of each other.

Question 21

Which of the following compounds has a plane of symmetry?

A)I and II
B)II and III
C)II,III,and IV
D)III and IV

Question 22

Which of the following structures has a different configuration from the other three?

A)I
B)II
C)III
D)IV

Question 23

What is the total number of possible stereoisomers for the following molecule?

A)2
B)4
C)6
D)8

Question 24

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system.

A)I > II > IV > III
B)IV > II > I > III
C)IV > I > II > III
D)III > II > I> IV

Question 25

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system.

A)I > III > IV > II
B)III > IV > I > II
C)IV > III > I > II
D)IV > I > III > II

Question 26

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system.

A)IV > III > I > II
B)IV > I > III > II
C)III > IV > I > II
D)II > I > III > IV

Question 27

How many stereogenic centers are present in fructose,a simple sugar?

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

Question 28

How many stereoisomers are possible for a molecule with formula CH₃CHBrCH(OH)CH₃?

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

Question 29

How many stereogenic centers are present in the following compound?

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

Question 30

How many isomers can be drawn (constitutional and stereoisomers)for dimethycyclopropane?

A)2
B)3
C)4
D)6

Question 31

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system.

A)III > I > II > IV
B)I > II > IV > III
C)III > II > IV > I
D)III > IV > II > I

Question 32

How many stereoisomers can be drawn for a molecule with formula CH₃CH(OH)CH(OH)CH₃?

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

Question 33

How many stereogenic centers are present in the following compound?

A)0
B)1
C)2
D)3

Question 34

How many stereogenic centers are present in the following compound?

A)0
B)1
C)2
D)3

Question 35

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system.

A)I > II > III > IV
B)II > I > IV > III
C)II > I > III > IV
D)I > II > IV > III

Question 36

How many stereogenic centers are present in menthol?

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

Question 37

How many stereogenic centers are present in gabapentin,used clinically to treat seizures and certain types of chronic pain?

A)0
B)1
C)2
D)3

Question 38

How many stereogenic centers are present in the following compound?

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

Question 39

How many stereogenic centers are present in the following molecule?

A)1
B)2
C)4
D)5

Question 40

How many chiral stereoisomers can be drawn for dimethycyclopropane?

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

Question 41

Which of the following cyclic molecules is a meso compound?

A)I
B)II
C)III
D)IV

Question 42

How many stereoisomers of 1,3-dibromocyclopentane exist?

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

Question 43

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 44

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 45

Which of the following compounds are meso?

A)Only I
B)Only II
C)I and II
D)Neither

Question 46

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 47

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 48

Which of the following structures has the R configuration?

A)Only I
B)Only II
C)Only I and II
D)I,II,and III

Question 49

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 50

Which of the following structures has the S configuration?

A)Only I
B)Only II
C)Only I and II
D)I,II,and III

Question 51

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 52

Which of the following is the definition for a pair of diastereomers?

A)A pair of stereoisomers with stereogenic centers but is not chiral.
B)A pair of stereoisomers that are superimposable mirror images of each other.
C)A pair of stereoisomers that are not superimposable mirror images of each other.
D)A pair of stereoisomers that are not mirror images of each other.

Question 53

Which of the following compounds can have a meso stereoisomer?

A)I
B)II
C)III
D)IV

Question 54

Which of the following statements about meso compounds is not true?

A)A meso compound generally has a plane of symmetry.
B)A meso compound and its mirror image are identical.
C)A meso compound is achiral.
D)A meso compound is chiral.

Question 55

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 56

Which of the following compounds is a meso compound?

A)(2R,3S)-dichlorobutane
B)(2R,3R)-dichlorobutane
C)(2R,3S)-3-chloro-2-butanol
D)(2R,3R)-3-chloro-2-butanol

Question 57

What is the relationship between the following compounds?

A)Constitutional isomers
B)Diastereomers
C)Enantiomers
D)Identical

Question 58

Which of the following structures has a different configuration from the other three?

A)I
B)II
C)III
D)IV

Question 59

Which of the following compounds does not have a plane of symmetry?

A)Only I and II
B)Only II
C)Only III and IV
D)Only I,II,and IV

Question 60

Which of the following structures has the R configuration?

A)Only I
B)Only II
C)Only I and II
D)I,II,and III

Question 61

A solution containing 0.08 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +4°.What is the specific rotation of the S enantiomer?

A)+50°
B)-40°
C)+40°
D)-50°

Question 62

A solution containing 0.4 g/mL of a pure S enantiomer is a 1 dm polarimeter rotates plane polarized light by +5.6°.What is the rotation of a solution containing 0.8 g/mL of the S enantiomer in the same polarimeter?

A)+5.6°
B)+11.2°
C)+2.8°
D)+1.4°

Question 63

A natural product was isolated in the laboratory,and its observed rotation was +10° when measured in a 1 dm sample tube containing 1.0 g of compound in 10 mL of H₂O.What is the specific rotation of this compound?

A)-10°
B)+100°
C)+10°
D)-100°

Question 64

Give the IUPAC name for the following compound:

A)(1R,2R)-1,2-dimethylcyclopentane
B)(1R,2S)-1,2-dimethylcyclopentane
C)(1S,2R)-1,2-dimethylcyclopentane
D)(1S,2S)-1,2-dimethylcyclopentane

Question 65

How much of the R enantiomer is present in 10 g of a mixture that has an enantiomeric excess of 30% of the S isomer?

A)3)0 g
B)3)5 g
C)6)5 g
D)7)0 g

Question 66

Give the IUPAC name for the following compound:

A)(1R,3R)-1-ethyl-3-methylcyclohexane
B)(1R,3S)-1-ethyl-3-methylcyclohexane
C)(1S,3R)-1-ethyl-3-methylcyclohexane
D)(1S,3S)-1-ethyl-3-methylcyclohexane

Question 67

What is the percent ee of a mixture that has 70% of one enantiomer and 30% of the other?

A)70
B)85
C)40
D)30

Question 68

Which of the following compounds are chiral?

A)I and II
B)II and III
C)III and IV
D)I and IV

Question 69

Give the IUPAC name for the following compound:

A)R-2,3-dimethylhexane
B)S-2,3-dimethylhexane
C)R-4,5-dimethylhexane
D)S-4,5-dimethylhexane

Question 70

Give the IUPAC name for the following compound:

A)R-3-methylhexane
B)S-3-methylhexane
C)R-4-methylhexane
D)S-4-methylhexane

Question 71

A reaction mixture is three parts of one enantiomer and one part of the other.What is the percent ee of this mixture?

A)75
B)40
C)65
D)50

Question 72

If a mixture has an ee of 90%,what is the percentage of each enantiomer?

A)65% : 35%
B)55% : 45%
C)80% : 20%
D)95% : 5%

Question 73

Which of the following compounds is identical to compound A?

A)I and II
B)II and III
C)I and III
D)II

Question 74

How many isomers (constitutional and stereoisomers)exist for dimethylcyclobutane?

A)3
B)4
C)5
D)6

Question 75

Give the IUPAC name for the following compound:

A)R-3-methylhexane
B)S-3-methylhexane
C)R-4-methylhexane
D)S-4-methylhexane

Question 76

Give the IUPAC name for the following compound:

A)(1R,3R)-1-ethyl-3-methylcyclohexane
B)(1R,3S)-1-ethyl-3-methylcyclohexane
C)(1S,3R)-1-ethyl-3-methylcyclohexane
D)(1S,3S)-1-ethyl-3-methylcyclohexane