Organic Chemistry A Brief Course International Edition 13th Edition by David J. Hart - Test Bank

Organic Chemistry A Brief Course International Edition 13th Edition by David J. Hart – Test Bank

 

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Chapter 5 — Stereoisomerism

 

MULTIPLE CHOICE

 

1. Which of the following objects is chiral?

A)	egg
B)	pencil
C)	cross country skis
D)	paperclip
E)	shoes

 

 

ANS:  E                    TOP:   Definitions

 

2. Chiral molecules that have nonsuperimposable mirror images are called:

A)	enantiomers
B)	diastereomers
C)	meso compounds
D)	stereogenic
E)	symmetrical

 

 

ANS:  A                    TOP:   Definitions

 

3. Which of the following molecules has a mirror plane of symmetry?

 

A)	1
B)	2
C)	3
D)	4
E)	all of them

 

 

ANS:  B                    TOP:   Definitions

 

4. What is the process that separates enantiomers?

A)	separation
B)	decoupling
C)	resetting
D)	resolution
E)	selective binding

 

 

ANS:  D                    TOP:   Definitions

 

5. A 50:50 mixture of enantiomers

A)	is a meso form.
B)	is a pair of diastereomers.
C)	is a racemic mixture.
D)	rotates plane polarized light.
E)	is a pair of conformers.

 

 

ANS:  C                    TOP:   Definitions

 

6. The terms that best describe the isomeric relationship between staggered and eclipsed ethane are

A)	configurational, achiral, diastereomers.
B)	conformational, chiral, enantiomers.
C)	conformational, achiral, diastereomers.
D)	configurational, chiral, enantiomers.
E)	conformational, achiral, enantiomers.

 

 

ANS:  C                    TOP:   Definitions

 

7. Which of the molecules below has a stereogenic carbon atom?

 

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

 

 

ANS:  B                    TOP:   Definitions

 

8. How many stereogenic centers are present in the following molecule?

 

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  B                    TOP:   Definitions

 

9. How many stereogenic centers are present in the following molecule?

 

A)	1
B)	2
C)	4
D)	6
E)	8

 

 

ANS:  B                    TOP:   Definitions

 

10. How many chiral stereoisomers can be drawn for CH₃CHClCHBrCH₃?

A)	1
B)	2
C)	3
D)	4
E)	8

 

 

ANS:  D                    TOP:   Definitions

 

11. How many stereogenic carbons are in the following molecule?

 

A)	0
B)	1
C)	2
D)	3
E)	4

 

 

ANS:  A                    TOP:   Definitions

 

12. How many stereoisomers can be obtained from the monobromination of pentane?

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  B                    TOP:   Definitions

 

13. How many stereoisomers with the formula CH₃CHICHICH₃ are possible?

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  C                    TOP:   Definitions

 

14. The number of stereogenic centers in progesterone is:

progesterone (no stereochemistry shown)

A)	2
B)	3
C)	4
D)	5
E)	6

 

 

ANS:  E                    TOP:   Definitions

 

15. The total number of possible stereoisomers of  is:

 

A)	2
B)	4
C)	6
D)	8
E)	0

 

 

ANS:  D                    TOP:   Definitions

 

16. The total number of possible stereoisomers of 1-bromo-2-chlorocyclopentane is:

A)	2
B)	4
C)	6
D)	8
E)	0

 

 

ANS:  B                    TOP:   Definitions

 

17. An unknown sample is tested with a polarimeter for optical activity.  The results of the test required no movement of the analyzer.  What samples would give this result?

A)	pure enantiomer
B)	meso compound
C)	racemic mixture
D)	both B and C
E)	none of these

 

 

ANS:  D                    TOP:   Optical Activity

 

18. An unknown sample is tested with a polarimeter for optical activity. The results of the test require movement of the analyzer. What samples would give this result?

A)	pure enantiomer
B)	meso compound
C)	racemic mixture
D)	both B and C
E)	none of these

 

 

ANS:  A                    TOP:   Optical Activity

 

19. Which of the following statements about enantiomers is INCORRECT?

A)	they cannot be differentiated by spectra
B)	they have the same melting and boiling points
C)	the mirror image of the R enantiomer is the S enantiomer
D)	the specific rotation of enantiomers has the same magnitude
E)	without exception, S enantiomers will rotate plane-polarized light to the left (counterclockwise)

 

 

ANS:  E                    TOP:   Optical Activity

 

20. The observed rotation for 100 mL of an aqueous solution containing 1 g of sucrose, placed in a 2-decimeter sample tube, is +1.33° at 25°C.  What is the specific rotation of sucrose?

A)	+66.5°
B)	+266°
C)	+41.5
D)	+133°
E)	108°

 

 

ANS:  A                    TOP:   Optical Activity

 

21. Which of the following molecules are the same?

 

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

 

 

ANS:  C                    TOP:   Relationships Between Stereoisomers

 

22. Which of the three molecules below is the enantiomer of the following molecule?

 

 

A)	I
B)	II
C)	III
D)	there are no enantiomers
E)	both II and III

 

 

ANS:  A                    TOP:   Relationships Between Stereoisomers

 

23. Which of the three molecules below is a diastereomer of the following molecule?

 

 

A)	I
B)	II
C)	III
D)	there are no diastereomers
E)	both I and II

 

 

ANS:  C                    TOP:   Relationships Between Stereoisomers

 

24. Which of the following are achiral conformers?

A)	staggered and eclipsed forms of ethane
B)	cis and trans-2-butene
C)	meso and (2R,3R)-2,3-dibromobutane
D)	(R) and (S)-lactic acid

 

 

ANS:  A                    TOP:   Relationships Between Stereoisomers

 

25. Which of the following would constitute a pair of enantiomers?

A)	staggered and eclipsed forms of ethane
B)	cis and trans-2-butene
C)	meso– and (2R,3R)-2,3-dibromobutane
D)	(2R,3R) and (2S,3S)-tartaric acid
E)	none of these

 

 

ANS:  D                    TOP:   Relationships Between Stereoisomers

 

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

A)	configurational, diastereomers.
B)	conformational, enantiomers.
C)	conformational, diastereomers
D)	configurational, enantiomers.
E)	configurational, cis/trans.

 

 

ANS:  A                    TOP:   Relationships Between Stereoisomers

 

27. The terms that best describe the relationship between (2R,3S)-2-bromo-3-chlorobutane and (2S,3R)-2-bromo-3-chlorobutane are

A)	configurational, achiral, diastereomers.
B)	conformational, chiral, diastereomers.
C)	configurational, chiral, enantiomers.
D)	conformational, chiral, enantiomers.
E)	configurational, chiral, diastereomers.

 

 

ANS:  C                    TOP:   Relationships Between Stereoisomers

 

28. Which of the following statements about the pair of molecules shown below is not true?

 

A)	They have the same boiling point.
B)	One rotates plane polarized light in the opposite direction from the other.
C)	They have the same density.
D)	One rotates plane polarized light a different number of degrees than the other.
E)	They are mirror images of each other.

 

 

ANS:  D                    TOP:   Relationships Between Stereoisomers

 

29. According to the R-S convention, which priority is correct for the following sets of groups?

A)	NH2 > Cl > CH3 > H
B)	Cl > NH2 > CH3 > H
C)	Cl > CH3 > NH2 > H
D)	H > Cl > CH3  > NH2
E)	CH3 > NH2 > Cl > H

 

 

ANS:  B                    TOP:   The R-S and E-Z Conventions

 

30. (R)-2-chlorobutane is correctly represented by which of the following:

 

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

 

 

ANS:  B                    TOP:   The R-S and E-Z Conventions

 

31. Which of the following groups has the highest priority for assigning R-S absolute configuration?

A)	CH2=CH–
B)	(CH3)2CH–
C)	(CH3)3C–
D)	CH3CH2–
E)	CH3–

 

 

ANS:  C                    TOP:   The R-S and E-Z Conventions

 

32. The correct IUPAC name for the following molecule is:

 

A)	(E)-2-bromo-3-chloro-5-methyl-2-hexene
B)	(E)-2-bromo-3-chloro-5-methyl-3-hexene
C)	(Z)-2-bromo-3-chloro-5-methyl-3-hexene
D)	(Z)-2-bromo-3-chloro-5-methyl-2-hexene
E)	(E)-5-bromo-4-chloro-2-methyl-4-hexene

 

 

ANS:  D                    TOP:   The R-S and E-Z Conventions

 

33. Which of the following structures is (E)-2,3-dichloro-2-pentene?

 

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  E                    TOP:   The R-S and E-Z Conventions

 

34. Of the following structures, how many are classified “E”?

 

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  C                    TOP:   The R-S and E-Z Conventions

 

35. Of the following structures, how many are classified “Z”?

 

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  C                    TOP:   The R-S and E-Z Conventions

 

36. Which of the following structures depicts (R)-3-ethyl-2,3-dimethylhexane?

A)		D)
B)		E)
C)

 

 

ANS:  B                    TOP:   The R-S and E-Z Conventions

 

37. The priority order for R/S nomenclature is

A)	—CH=CH2 > —OH > —CH3 > —CH2CH3
B)	—OH > —CH2CH3 > —CH=CH2 > —CH3
C)	—OH > —CH=CH2 > —CH2CH3 > —CH3
D)	—CH3 > —CH2CH3 > —CH=CH2 > —OH
E)	—CH2CH3 > —CH3 > —CH=CH2 > —OH

 

 

ANS:  C                    TOP:   The R-S and E-Z Conventions

 

38. Which name describes the following structure?

 

A)	(R)-3-methyl-1-penten-3-ol
B)	(S)-3-methyl-1-penten-3-ol
C)	(R)-3-ethyl-1-buten-3-ol
D)	(R)-3-methyl-1-pentyn-3-ol
E)	(S)-3-ethyl-1-buten-3-ol

 

 

ANS:  A                    TOP:   The R-S and E-Z Conventions

 

39. Which name describes the following structure?

 

A)	(R)-4-methyl-1-hexen-4-ol
B)	(S)-4-ethyl-1-penten-4-ol
C)	(R)-4-ethyl-1-penten-3-ol
D)	(S)-4-methyl-1-hexen-4-ol
E)	(S)-4-methyl-1-hexyn-4-ol

 

 

ANS:  D                    TOP:   The R-S and E-Z Conventions

 

40. What is correct name for the following structure?

 

A)	(R,S)-2,3-dichlorobutane
B)	(2R,3S)-2,3-dichlorobutane
C)	(2S,3S)-2,3-dichlorobutane
D)	(2R,3R)-2,3-dichlorobutane
E)	none of these

 

 

ANS:  D                    TOP:   Fischer and Newman Projections

 

41. What is the absolute configuration around C-2 and C-3?

 

A)	R, R
B)	S, S
C)	R, S
D)	S, R
E)	E, Z

 

 

ANS:  A                    TOP:   Fischer and Newman Projections

 

42. The absolute configuration around the stereogenic center of the molecule below is:

 

A)	R
B)	S
C)	E
D)	Z
E)	trans

 

 

ANS:  A                    TOP:   Fischer and Newman Projections

 

43. The Fischer projection formula for (S)-lactic acid (2-hydroxypropanoic acid) is

A)		D)
B)		E)
C)

 

 

ANS:  E                    TOP:   Fischer and Newman Projections

 

44. The Fischer projection that represents the same molecule as  is:

 

A)		D)
B)		E)
C)

 

 

ANS:  C                    TOP:   Fischer and Newman Projections

 

45. represents

 

A)	(2R,3R)-2,3-butanediol.
B)	(2S,3S)-2,3-butanediol.
C)	the most stable conformer of (2R,3R)-2,3-butanediol.
D)	the least stable conformer of (2R,3R)-2,3-butanediol.
E)	meso-2,3-butanediol.

 

 

ANS:  E                    TOP:   Fischer and Newman Projections

 

46. Which one of the following structures represents a meso compound?

A)		D)
B)		E)
C)

 

 

ANS:  A                    TOP:   Fischer and Newman Projections

 

47. When (R)-3-bromo-2-methyl-1-butene is reacted with HBr, two stereoisomers are formed.  What is the relationship of these stereoisomers?

A)	enantiomers
B)	meso compounds
C)	diastereomers
D)	E
E)	Z

 

 

ANS:  C                    TOP:   Stereochemistry and Chemical Reactions

 

48. Treating 1-butene with HBr produces a product with one stereogenic carbon.  What is the name of the product?

A)	2-bromo-1-butene
B)	1-bromobutane
C)	(R)-2-bromobutane
D)	(S)-2-bromobutane
E)	both C and D in equal amounts

 

 

ANS:  E                    TOP:   Stereochemistry and Chemical Reactions

 

49. When (S)-3-bromo-1-butene is treated with HBr, two stereoisomeric products form.  What is the relationship of these two products?

A)	enantiomers
B)	diastereomers
C)	meso compounds
D)	racemic mixture
E)	cis/trans

 

 

ANS:  B                    TOP:   Stereochemistry and Chemical Reactions

 

50. How many stereogenic carbons are produced from the following sequence of reactions?

 

 

A)	1
B)	2
C)	3
D)	4
E)	5

 

 

ANS:  B                    TOP:   Stereochemistry and Chemical Reactions

 

51. Enantiomers may differ in the following property:

A)	the rate at which they react with a chiral reagent
B)	boiling point
C)	melting point
D)	number of degrees they rotate plane polarized light
E)	solubility in water

 

 

ANS:  A                    TOP:   Stereochemistry and Chemical Reactions

 

52. The product of addition of bromine to (R)-3-buten-2-ol will be

A)	a 50:50 mixture of enantiomers.
B)	a mixture of enantiomers formed in unequal amounts.
C)	a 50:50 mixture of diastereomers.
D)	a mixture of diastereomers formed in unequal amounts.
E)	optically inactive.

 

 

ANS:  D                    TOP:   Stereochemistry and Chemical Reactions