Deck 5: Stereochemistry

Question 1

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

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

Answer 1

3

Question 2

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

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

Answer 2

2

Question 3

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.

Answer 3

A pair of stereoisomers that are not superimposable mirror images of each other.

Question 4

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 5

How many stereogenic centers are present in the following compound?

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

Question 6

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 7

What is the relationship between the following two compounds?

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

Question 8

How many stereogenic centers are present in the following compound?

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

Question 9

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.

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

Which of the following molecules are chiral?

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

Question 12

How many stereogenic centers are present in the following molecule?

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

Question 13

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.

Question 14

Which of the following molecules are achiral?

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

Question 15

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 16

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

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

Question 17

How many stereogenic centers are present in the following compound?

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

Question 18

Which of the following statements about constitutional isomers if 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 19

How many stereogenic centers are present in menthol?

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

Question 20

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 21

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 22

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 23

How many chiral stereoisomers can be drawn for dimethycyclopropane?

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

Question 24

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 25

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 26

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 27

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

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

Question 28

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

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

Question 29

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

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

Question 30

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

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

Question 31

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

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

Question 32

What is the relationship between the following compounds?

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

Question 33

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 34

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 35

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 36

What is the relationship between the following compounds?

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

Question 37

What is the relationship between the following compounds?

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

Question 38

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 39

What is the relationship between the following compounds?

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

Question 40

How many stereogenic centers are present in the following compound?

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

Question 41

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 42

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 43

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 44

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 45

Which of the following cyclic molecules is a meso compound?

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

Question 46

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

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

Question 47

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 48

What is the relationship between the following compounds?

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

Question 49

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 50

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 51

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 52

Which of the following compounds can have a meso stereoisomer?

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

Question 53

Which of the following compounds are meso?

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

Question 54

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 55

What is the relationship between the following compounds?

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

Question 56

How many stereoisomers of 1,3-dibromocyclopentane exist?

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

Question 57

What is the relationship between the following compounds?

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

Question 58

What is the relationship between the following compounds?

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

Question 59

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