Stereochemistry MCQs [Organic Chemistry]

1. Cis-2-Butene on reaction with bromine gives 2,3-dibromobutane which is

(A) Racemic mixture

(B) Meso-isomer

(C) Dextroisomer

(D) Laevoisomer

2. How many stereoisomers are possible for CH3CH=CHCHCH(Br)CH3?

(A) 2-Geometrical isomers

(B) 2-Geometrical and 2 optical isomers

(C) 2-Geometrical and 1 optical isomer

(D) 2 Optical isomers

3. Process of separating the racemic mixture into optically active isomers is famous as

(A) Resolution

(B) Racemization

(C) Walden inversion

(D) Epimerization

4. Lactic acid is a molecule which shows

(A) Epimersim

(B) Metamerism

(C) Tautomerism

(D) Optical isomerism

5. Different arrangements of groups in space which can be converted into one another by rotation around a single bond are known as _____.

(A) Configuration

(B) Metamers

(C) Enantiomers

(D) Conformations

6. Stereoisomers not related to each other as object and mirror image are known as

(A) Enantiomers

(B) Conformations

(C) Antipodes

(D) Diastereoisomers

7. Stereoisomers that can be interconverted by rotation about a single bond are known as _____.

(A) Tautomers

(B) Chain isomers

(C) Functional isomers

(D) Conformers

8. Geometrical isomerism emerges due to which reason?

(A) High electron density between two substituted carbon

(B) Both A & B

(C) Restricted rotation of substituents around double bond

(D) None of these

9. In E-Z nomenclature of stereoisomers, E will be assigned to

(A) If higher priority groups are on the same direction

(B) The geometrical isomers having higher priority groups on opposite direction

(C) Both A & B

(D) None of these

10. In optical isomerism

(A) Dextrorotatory are represented by (+)

(B) Laevorotatory are represented by (-) sign

(C) Sometimes levo and sometimes dextro are represented by (-) sign

(D) Both A & B are wrong

11. Geometrical isomerism can be exhibited by compounds having _____.

(A) –N=N–

(B) All of these

(C) >C=C<

(D) >C=N–

12. Which of the mentioned molecules can exhibit geometrical isomerism?

(A) CH3CH=C(CH3)2

(B) (CH3)2C=CH2

(C) CH3CH=CHCH3

(D) CH3CH=CH2

13. How many optical isomers are possible for CH(OH)COOH CH—(Br) COOH?

(A) 2

(B) 3

(C) 4

(D) 8

14. Which of the mentioned property has a higher value for trans-isomer as compared to cis-isomer?

(A) Melting point

(B) Dipole moment

(C) Density

(D) Boiling point

15. Which configuration has lowest potential energy?

(A) Eclipsed

(B) Staggered

(C) Skew

(D) All have same energy

16. D(+) glyceraldehyde has the absolute configuration

(A) Z-

(B) S-

(C) E-

(D) R-

17. According to R, S system the correct order of priority of the following groups is

–CHO > –CH2OH’)”> (A) –CH2OH > –CHO > –COOH

–CHO > –CH2OH’)”> (B) –COOH > –CHO > –CH2OH

–CHO > –CH2OH’)”> (C) –CH2OH > –COOH > –CHO

–CHO > –CH2OH’)”> (D) –COOH > –CH2OH > –CHO

18. The angle of rotation of plane polarized light in polarimeter relies on _____.

(A) Concentration of substance

(B) All A, B, and C

(C) Length of polarimeter tube

(D) Nature of the substance

19. Which of the mentioned compounds shows tautomerism?

(A) Chloroethane

(B) Ethanol

(C) Ethoxyethane

(D) Nitroethane

20. 2-Butanol is optically active because it contains

(A) An asymmetric carbon atom

(B) A plane of symmetry

(C) Centre of symmetry

(D) A hydroxyl group

21. Which of the mentioned compound will be optically active?

(A) Acetic acid

(B) Meso-tartaric acid

(C) Lactic acid

(D) Succinic acid

22. What is the possible number of optical isomers for a compound containing 2 dissimilar asymmetric carbon atoms?

(A) 2

(B) 4

(C) 6

(D) 8

23. Which of the mentioned statements is wrong about enantiomers?

(A) Rotate plane of polarized light

(B) Have the same melting points

(C) Are superimposable mirror images

(D) Non superimposable mirror images

24. Enantiomers have __________ characteristics?

(A) React with optically active molecules at the same rate

(B) Rotate ordinary light

(C) Are superimposable mirror images

(D) Have the same melting point

25. It is possible to distinguish between optical isomers

(A) By polarimetry

(B) By mass spectrometry

(C) By IR spectroscopy

(D) Using chemical tests

26. Plane polarized light is affected by

(A) Chiral molecules

(B) All polymers

(C) Identical molecules

(D) All biomolecules

27. A molecule is said to be chiral if it __________.

(A) Contains plane of symmetry

(B) Contains center of symmetry

(C) Can be superimposed on its mirror image

(D) Cannot be superimposed on its mirror image

28. An optically active compound _____.

(A) Must contain at least four carbons

(B) In solution always gives negative reading in polarimeter

(C) Must always contain an asymmetric carbon atom

(D) When in solution rotates the plane of polarized light

29. Maleic acid and fumaric acid are_____.

(A) Homologous

(B) Enantiomers

(C) Geometrical isomers

(D) Diastereoisomers

30. Which of the mentioned are structural isomers?

(A) Functional isomers

(B) All A, B, and C

(C) Chain isomers

(D) Position isomers

31. n-Butane and 2-methylpropane are examples of ______.

(A) Functional isomers

(B) Chain isomers

(C) Position isomers

(D) Tautomers

32. 1-Propanol and 2-propanol are examples of____.

(A) Tautomers

(B) Chain isomers

(C) Functional isomers

(D) Position isomers

33. Acetone and diethyl ether are examples of

(A) Functional isomers

(B) Chain isomers

(C) Position isomers

(D) Tautomers

34. Compounds HCN and HNC are _____.

(A) Conformers

(B) Metamers

(C) Tautomers

(D) Functional isomers

35. Alkyl cyanide and alkyl isocyanides are _____.

(A) Functional isomers

(B) Tautomers

(C) Metamers

(D) Geometric isomers

36. Several compounds corresponding to molecular formula C4H10 are _____.

(A) Chain isomers

(B) Functional isomers

(C) Tautomers

(D) Position isomers

37. The device which is helpful and used to measure the optical activity is known as

(A) Conductivity meter

(B) Polari scope

(C) Potentiometer

(D) Photometer

38. In Relative Configuration D & L are assigned __________.

(A) Number of chiral centers

(B) In relation to number of possible stereoisomers

(C) In relation to glyceraldehyde

(D) None of these

39. Epimers are the stereoisomer of compound which

(A) Differ in configuration at particular chiral center in a compound having more than one chiral center

(B) Differ in configuration at one chiral center

(C) Differ in configuration at one chiral center only in cyclic compounds

(D) None of these

40. In relative stability of conformational isomers of n-butane

(A) Both lies at lower energy but sometimes anti goes to higher energy

(B) Skew form lies at lower energy

(C) Anti-form lies at lowest energy

(D) None of these

41. Which of the mentioned compounds show optical activity?

(A) Maleic acid

(B) Oxalic acid

(C) Aldehyde

(D) Sucrose

42. Stereoisomers that are related like an object and its mirror image non-super imposable are known as

(A) Chain isomers

(B) Enantiomers

(C) Functional isomers

(D) Tautomers

43. The configuration of a compound with reference to the arbitrarily assigned configuration is known as

(A) Absolute configuration

(B) Retention of configuration

(C) None of A, B, and C

(D) Relative configuration

44. An equimolar mixture of a pair of enantiomers is known as

(A) Racemate mixture

(B) Ideal mixture

(C) Real mixture

(D) All A, B, and C

45. Which of the mentioned is an element of symmetry?

(A) All A, B, and C

(B) Plane of symmetry

(C) Proper rotation

(D) Centre of inversion

46. Which of the mentioned methods is helpful and used for resolution of racemic mixture?

(A) Physical method

(B) Biological method

(C) All A, B, and C

(D) Chemical method

47. The functional isomers of ether are

(A) Alcohol

(B) Ketones

(C) Aldehydes

(D) Hydrocarbons

48. The least cyclohexane is stable

(A) Chair

(B) Boat

(C) Half chair

49. Which of the mentioned molecules can exhibit geometrical isomerism?

(A) CH3CH=CHCH3

(B) CH3CH=CH₂

(C) (CH3)2C=CH2

(D) CH3CH=C(CH3)2

50. Stereoisomers not related to each other as object and mirror image are known as

(A) Enantiomers

(B) Antipodes

(C) Conformations

(D) Diastereoisomers

51. Asymmetric center is characterized by which of the following?

(A) Having more than one functional groups attached to carbon

(B) Sp3 carbon with 4 different groups attached to carbon

(C) Not having mirror image after a rotation of 180 degree

(D) All of A, B, and C

52. Which statement is true regarding Optical activity?

(A) Measure to evaluate degree of rotation of substituents in a chiral molecule

(B) The ability to rotate the plane of plane–polarized light

(C) To identify the direction of light (right or left) when it is targeted to chiral molecule

(D) None of these

53. Chiral compounds are _______ forever

(A) Optically active

(B) Have acidic protons

(C) Have diastereomers

(D) Have enantiomers

54. Examples of ______ are Diethyl ether and methyl propyl ether.

(A) Chain isomers

(B) Metamers

(C) Stereoisomers

(D) Tautomers

55. Which is not a type of stereoisomer?

(A) Conformational isomers

(B) Optical isomers

(C) Tautomers

(D) Geometrical isomers

56. Two structural isomers which differ in the relative positions of their atoms and are readily interconvertible are known as

(A) Functional isomers

(B) Chain isomers

(C) Tautomers

(D) Position isomers

57. Isomers that have the same structural formula but differ in the arrangement of atoms in the three dimensional space are known as __.

(A) Stereoisomers

(B) Chain isomers

(C) Functional isomers

(D) Tautomers

58. Benzene has

(A) All of A, B, and C

(B) Plane of symmetry

(C) Centre of symmetry

(D) Axis of symmetry

59. Asymmetric carbon is that

(A) Both a & b

(B) Which has chiral center

(C) Which is attached with three different types of substituents

(D) Which is attached with four different types of substituents

60. Enantiomers are the stereoisomers which

(A) Have at least one chiral center

(B) Have at least two chiral centers

(C) Not superimposable to their mirror images

(D) None of these

61. What is the formula for calculation of Number of stereoisomers?

(A) (n) is number of substituents

(B) (n) is number chiral centers

(C) (n) is number carbon atoms

(D) None of these

62. Stereochemistry studies the compound

(A) Optical activity

(B) Rotation of substituents around single bond

(C) Distribution of substituents in carbon skeleton

(D) Spatial arrangement

63. The energy difference between staggered and eclipsed conformation of ethane is

(A) 25 kJ/mol

(B) 30 kJ/mol

(C) 100 kJ/mol

(D) 12.5 kJ/mol

64. What is the total number of conformations of ethane?

(A) 3

(B) 7

(C) Infinite

(D) 5

65. What is the energy difference between boat and chair conformation of cyclohexane?

(A) 44 kJ/mol

(B) 12.5 kJ/mol

(C) 100 kJ/mol

(D) 50 kJ/mol

66. Various compounds corresponding molecular formula C4H10 are ______.

(A) Chain isomers

(B) Position isomers

(C) Tautomers

(D) Functional isomers

67. Which of the mentioned methods helpful and used for the determination of configuration of geometrical isomers?

(A) Dipole moment

(B) Melting point

(C) All A, B, and C

(D) Solubility

68. Anthracene is isomeric with which of the following?

(A) Physical method

(B) Naphthalene

(C) Phenanthrene

(D) Benzene