Question 1

Which of the following structures has a center of symmetry (i.e., center of inversion) ?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) A) and D)
F) B) and C)

Question 2

Which of the following structures is chiral?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) A) and C)
F) A) and D)

Question 3

What is the relationship between the following pair of structures?

Accepted Answer

A)   They are enantiomers
B)   They are diastereomers
C)   The are constitutional isomers
D)   They are identicalE) A) and B)
F) A) and C)

Question 4

Which of the following is the definition of chirality?

Accepted Answer

A)   The non-superposability of an object on its mirror image
B)   The superposability of an object on its mirror image
C)   A molecule that has a carbon atom with four different substituents
D)   A molecule with a mirror imageE) C) and D)
F) B) and C)

Question 5

The terms that best describe the relationship between (2R,3S)-2,3-butanediol and (2S,3S)-2,3-butanediol are configurational and diastereomers.

Accepted Answer

A) True 
 B)False

Question 6

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

Accepted Answer

A)   2
B)   3
C)   4
D)   5E) A) and C)
F) None of the above

Question 7

Complete the following diagram so that it represents (R)-2-bromobutane.

Accepted Answer

The answer of Complete the following diagram so that it...

Question 8

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

Accepted Answer

A)   3
B)   5
C)   7
D)   9E) A) and B)
F) A) and C)

Question 9

How many stereoisomers of 3-bromo-2-butanol, CH3CH(OH) CHBrCH3, exist?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) B) and D)
F) A) and B)

Question 10

Which of the following Newman projections represents (2R,3R) -dibromobutane?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) B) and C)
F) A) and B)

Question 11

An unknown sample is tested with a polarimeter for optical activity. The results of the test required no movement of the analyzer. This sample could be either a meso compound or a racemic mixture.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following Newman projections represents meso-2,3-dibromobutane?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) A) and B)
F) A) and C)

Question 13

How much of the R enantiomer is present in 10 g of a mixture which has an enantiomeric excess of 20% of the S isomer?

Accepted Answer

A)   1 g
B)   2 g
C)   4 g
D)   6 gE) A) and D)
F) B) and D)

Question 14

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

Accepted Answer

A)   A pair of structures that are superposable mirror images of one another
B)   A pair of stereoisomers that are non-superposable mirror images of one another
C)   A pair of stereoisomers that are not mirror images of one another
D)   A pair of stereoisomers that have equal specific rotationsE) A) and B)
F) All of the above

Question 15

In muscle tissue only (+)-lactic acid is found but in sour milk both (+)-lactic acid and (-)-lactic acid are present. This difference might be explained by the fact that the production of lactic acid in muscle tissue is catalyzed by biological catalysts or enzymes.

Accepted Answer

A) True 
 B)False

Question 16

Complete the following zig-zag structure so that it represents (2R,3R)-3-chlorobutan-2-ol.

Accepted Answer

The answer of Complete the following zig-zag structure so that...

Question 17

Complete the following zig-zag structure so that it represents (2S,3R)-2,3-dibromobutane.

Accepted Answer

The answer of Complete the following zig-zag structure so that...

Question 18

Complete the following diagram so that it represents (R)-2-bromobutane.

Accepted Answer

The answer of Complete the following diagram so that it...

Question 19

Which of the following structures is different from the other three?

Accepted Answer

A)   1
B)   2
C)   3
D)   4E) B) and C)
F) None of the above

Question 20

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

Accepted Answer

A)   A pair of structures that are superposable mirror images of one another
B)   A pair of stereoisomers that are non-superposable mirror images of one another
C)   A pair of stereoisomers that are not mirror images of one another
D)   A pair of stereoisomers that have equal specific rotationsE) A) and D)
F) A) and C)

Exam 3: Stereoisomerism and Chirality

Which of the following Newman projections represents meso-2,3-dibromobutane?

Correct AnswerverifiedShow Answer

In muscle tissue only (+)-lactic acid is found but in sour milk both (+)-lactic acid and (-)-lactic acid are present. This difference might be explained by the fact that the production of lactic acid in muscle tissue is catalyzed by biological catalysts or enzymes.

Correct AnswerverifiedShow Answer

Which of the following Newman projections represents (2R,3R) -dibromobutane?

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Which of the following structures is different from the other three?

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Complete the following zig-zag structure so that it represents (2S,3R)-2,3-dibromobutane.

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An unknown sample is tested with a polarimeter for optical activity. The results of the test required no movement of the analyzer. This sample could be either a meso compound or a racemic mixture.

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How much of the R enantiomer is present in 10 g of a mixture which has an enantiomeric excess of 20% of the S isomer?

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What is the relationship between the following pair of structures?

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Which of the following is the definition of chirality?

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

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

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Which of the following structures is chiral?

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

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Complete the following diagram so that it represents (R)-2-bromobutane.

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

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Which of the following structures has a center of symmetry (i.e., center of inversion) ?

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The terms that best describe the relationship between (2R,3S)-2,3-butanediol and (2S,3S)-2,3-butanediol are configurational and diastereomers.

Correct AnswerverifiedShow Answer

How many stereoisomers of 3-bromo-2-butanol, CH3CH(OH) CHBrCH3, exist?

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Complete the following diagram so that it represents (R)-2-bromobutane.

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Complete the following zig-zag structure so that it represents (2R,3R)-3-chlorobutan-2-ol.

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How many stereoisomers of 3-bromo-2-butanol, CH₃CH(OH) CHBrCH₃, exist?

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