semester iv pharmaceutical organic chemistry - iii

Ms. B. B. Vaghasia, Assistant Professor, Faculty of Pharmacy, Dr. Subhash Technical Campus, Junagadh

SEMESTER IV

PHARMACEUTICAL ORGANIC

CHEMISTRY - III

(BP401TT)

Multiple Choice Questions

(Chapter 1 & 2 – Stereochemistry)

(Chapter 3 – Heterocyclic compound – I)

PHARMACEUTICAL ORGANIC CHEMISTRY-III (BP401TT)

Faculty of Pharmacy, Dr. Subhash Technical Campus, Junagadh

1) 1 Hexane and 3-methylpentane are examples of:

a. Enantiomers.

b. Stereoisomer.

c. Diastereomers.

d. Constitutional isomers.

Ans. – d

2) Cis-trans isomers are:

a. Diastereomers.

b. Enantiomers.

c. Geometric isomers.

d. Constitutional isomers.

Ans. – c

3) (2R,4S) –2,4–Dichloropentane and (2S,4R)-2,4-dichloropentane are:

a. Enantiomers

b. Diastereomers

c. identical

d. conformational isomers

Ans. – c

4) Which of the following molecules is achiral?

a. (2R,3R)-2,3-Dichloropentane

b. (2R,3S)-2,3-Dichloropentane

c. (2S,4S)-2,4-Dichloropentane

d. (2S,4R)-2,4-Dichloropentane

Ans. – d

5) Which statement is not true for a meso compound?

a. The specific rotation is 0º.

b. There are one or more planes of symmetry.

c. More than one stereogenic center must be present.

d. The stereo chemical labels, (R) and (S), must be identical for each stereogenic centre.

Ans. – d

6) Which is a meso compound?

a. (2R,3R)-2,3-Dibromobutane

b. (2R,3S)-2,3-Dibromopentane

c. (2R,4R)-2,4-Dibromopentane



d. (2R,4S)-2,4-Dibromopentane

Ans.- d

7) What is the percent composition of a mixture of (S)-(+)-2-butanol,[!] D/25 = +13.52º,

and (R)-(-)-2-butanol,[!] D/25 = -13.52º, with a specific rotation [!] D/25 = +6.76º?

a. 75%(R) 25%(S)

b. 25%(R) 75%(S)

c. 50%(R) 50%(S)

d. 67%(R) 33%(S)

Ans. – b

8) Which one of the following can exist in optically active forms?

a. cis-1,3-Dichlorocyclohexane

b. trans-1,3-Dichlorocyclohexane

c. cis-1,4-Dichlorocyclohexane

d. trans-1,4-Dichlorocyclohexane

Ans. – b

9) Which of these is a comparatively insignificant factor affecting the magnitude of

Specific optical rotation?

a. Concentration of the substance of interest

b. Purity of the sample

c. Temperature of the measurement

d. Length of the sample tube

Ans. – c

10) What can be said with certainty if a compound has [!] D/25 = -9.25º ?

a. The compound has the (S) configuration.

b. The compound has the (R) configuration.

c. The compound is not a meso form.

d. The compound possesses only one stereogenic center.

Ans. – c

11) An alkane which can exhibit optical activity is:

a. Neopentane

b. Isopentane

c. 3–Methylpentane

d. 3–Methylhexane

Ans. – d



12) In the absence of specific data, it can only be said that (R)–2–bromopentane is:

a. Dextrorotatory (+).

b. Levorotatory (–).

c. Optically inactive.

d. Chiral.

Ans. – d

13) If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15º in a 2 dm

tube, the specific rotation is:

a. +50º

b. +25º

c. +15º

d. +7.5º

Ans. – b

14) Which compound would show optical activity?

a. cis 1,4- Dimethylcyclohexane

b. trans 1,4- Dimethylcyclohexane

c. cis 1,4- Dimethylcycloheptane

d. trans 1,4- Dimethylcycloheptane

Ans. – d

15) Of the compounds which correspond to the general name "dichlorocyclobutane", how many are

optically active?

a. 0

b. 1

c. 2

d. 3

Ans. – c

16) Which of the following is true of any (S)-enantiomer?

a. It rotates plane-polarized light to the right.

b. It rotates plane-polarized light to the left.

c. It is a racemic form.

d. It is the mirror image of the corresponding (R)-enantiomer.

Ans. – d

17) Enantiomers are:

a. Molecules that have a mirror image.



b. Molecules that have at least one stereogenic center.

c. Non-superposable molecules.

d. Non-superposable molecules that are mirror images of each other.

Ans. – d

18) Which of the following is NOT true of enantiomers? They have the same:

a. Boiling point.

b. Melting point.

c. Specific rotation.

d. Density.

Ans. – c

19) Which statement is true of 1,3-dimethylcyclobutane?.

a. Only one form of the compound is possible.

b. Two diastereomeric forms are possible.

c. Two sets of Enantiomers are possible.

d. Two enantiomeric forms and one meso comp.

Ans. – b

20) CH3CHBrCH2CHClCH3 is the generalized representation of what number of stereo isomers?

a. 3

b. 4

c. 5

d. 6

Ans. – b

21) For the generalized structure BrCH2CHClCH2CHClCH2Br there exists what number of

stereoisomers?

a. 2

b. 3

c. 4

d. 6

Ans. – c

22) How many discrete dimethylcyclopropanes are there?

a. 2

b. 3

c. 4

d. 5



Ans. – c

23) What is the molecular formula for the alkenes of smallest molecular weight which possesses a

stereogenic center?

a. C4H10

b. C5H12

c. C6H14

d. C7H16

Ans. – d

24) How many chiral stereoisomers can be drawn for CH3CHFCHFCH (CH3)2?

a. 1

b. 2

c. 3

d. 4

Ans. – d

25) How many different compounds are there which correspond to the general name "3-(1-

methylbutyl) cyclobutanol”?

a. 2

b. 4

c. 6

d. 8

Ans. – b

26) Which of the statements below correctly describes an achiral molecule?

a. The molecule has a nonsuperimposable mirror image.

b. The molecule exhibits optical activity when it interacts with plane-polarized light.

c. The molecule has an enantiomer.

d. The molecule might be a meso form.

Ans. – d

27) Which of the following statements correctly pertains to a pair of enantiomers?

a. They rotate the plane of polarized light by exactly the same amount and in opposite

directions.

b. They rotate the plane of polarized light by differing amounts and in opposite directions.

c. They rotate the plane of polarized light by differing amounts and in the same direction.

d. They have different melting points.

Ans. – a



28) A mixture of equal amounts of two enantiomers __________.

a. is called a racemic mixture

b. is optically inactive

c. implies that the enantiomers are meso forms

d. both A and B

Ans. – d

29) __________ is the use of an optically active reagent or catalyst to convert an optically inactive

starting material into an optically active product.

a. Asymmetric induction

b. Racemization

c. Optical reduction

d. Meso effection

Ans. – a

30) Which of the following statements is (are) true for the compound (R)-2-butanol?

a. This compound is chiral.

b. This compound is optically active.

c. This compound has an enantiomer.

d. all of the above

Ans. – d

31) Which of the following statements is (are) true for the compound (3R, 4R)-3,4-dimethylhexane?


b. The enantiomer of this compound is (3S, 4S)-3,4-dimethylhexane.

c. This compound is a diastereomer of (3R, 4S)-3,4-dimethylhexane.

d. all of the above

Ans. – d

32) Which of the following statements is (are) true for the compound cis-1,2-dichlorocyclopropane?


b. The enantiomer of this compound is trans-1,2-dichlorocyclopropane.

c. This compound contains no asymmetric carbons.

d. none of the above

Ans. – d

33) How many asymmetric carbon atoms are present in the following compound?



a. 0

b. 1

c. 2

d. 3

Ans. – b

34) How many chiral carbon atoms are present in the following compound?

a. 0

b. 1

c. 2

d. 3

Ans. – a

35) Which of the following terms correctly describe(s) the structural relationship between cis-1,3-

dimethylcyclopentane and trans-1,3-dimethylcyclopentane?

a. enantiomers

b. diastereomers

c. geometric isomers

d. both B and C

Ans. – d

36) How many diastereomers are there of the molecule shown below?

a. 0

b. 2

c. 4



d. 6

Ans. – d

37) How many enantiomers are there of the molecule shown below?

a. 0

b. 2

c. 4

d. 6

Ans. – a

38) What term describes the structural relationship between (E)- and (Z)-2-pentene?

a. Constitutional isomers

b. Enantiomers

c. Geometric isomers

d. Conformers

Ans. – c

39) Compounds which have different arrangements of atoms in space while having same atoms

bonded to each other are said to have

a. position isomerism

b. functional group isomerism

c. chain isomerism

d. stereoisomerism

Ans. – d

40) Which of the following can make difference in optical isomers?

a. heat

b. temperature

c. polarized light

d. pressure

Ans. – c



41) Which of the following terms best describes the following pair of molecules?

a. Isomers

b. Constitutional isomers

c. Configurational isomers

d. Geometrical isomers

Ans. – d

42) What is the relationship between the two groups in the following molecules?

a. They are equatorial to one another

b. They are axial to one another

c. They are cis to one another

d. They are trans to one another

Ans. – c

. 43) What is the stereochemical relationship between the following two molecules?

a. Geometrical isomers

b. Enantiomers

c. Diastereomers

d. Identical

Ans. – d

44) Which of the following is an alkane which can exhibit optical activity?

a. Neopentane

b. Isopentane

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-stereochemistry-q4.png





c. 3–Methylpentane

d. 3–Methylhexane

Ans. – d

45) Hexane and 3-methylpentane are examples of:

a. enantiomers.

b. stereoisomers.

c. diastereomers.

d. constitutional isomers.

Ans. – d

46) Which of these is a comparatively insignificant factor affecting the magnitude of specific optical

rotation.

a. Concentration of substance of interest

b. Temperature of measurement

c. Length of the sample tube

d. All of the above

Ans. – d

47) How many chiral stereoisomers can be drawn for CH3CHFCHFCH(CH3)2?

a. 2

b. 4

c. 6

d. 8

Ans. – b

48) How many different compounds are there which correspond to the general name "3-(1-

methylbutyl)cyclobutanol”?

a. 2

b. 4

c. 6

d. 8

Ans. – b

49) Which of the following is NOT true of enantiomers? They have the same:

a. boiling point.

b. melting point.

c. specific rotation.

d. chemical reactivity toward achiral reagents.



Ans. – d

50) Which statement is true for 1,3-dimethylcyclobutane?

a. Only one form of the compound is possible

b. Two diastereomeric forms are possible.

c. Two enantiomeric forms and one meso compound are possible.

d. None of the above.

Ans. – b

51) Which of the following is true of any (S)-enantiomer?

a. It rotates plane-polarized light to the right.

b. It rotates plane-polarized light to the left.

c. It is a racemic form.

d. It is the mirror image of the corresponding (R)-enantiomer.

Ans. – d

52) If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15º

in a 2 dm tube, the specific rotation is:

a. +50º

b. +25º

c. +15º

d. +7.5º

Ans. – b

53) In the absence of specific data, it can only be said that (R)–2–bromopentane is:

a. dextrorotatory (+).

b. levorotatory (–).

c. analogous in absolute configuration to (R)–2–bromopentane.

d. optically inactive.

Ans. – c

54) Which is a meso compound?

a. (2R,3R)-2,3-Dibromobutane

b. (2R,3S)-2,3-Dibromopentane

c. (2R,4R)-2,4-Dibromopentane

d. (2R,4S)-2,4-Dibromopentane

Ans. – d

55) Which is achiral from the following molecules?



a. (2R,3R)-2,3-Dichloropentane

b. (2R,3S)-2,3-Dichloropentane

c. (2S,4S)-2,4-Dichloropentane

d. (2S,4R)-2,4-Dichloropentane

Ans. – d

56) Those stereoisomers which can be interconverted only by breaking and remaking of covalent

bonds are called as____

a. Chain isomers

b. Positional isomers

c. Configurational isomers

d. Conformational isomers

Ans. – c

57) Those stereoisomers which can be interconverted by simple rotation about sigma bonds are called

as____

a. Conformational isomers

b. Functional isomers

c. Geometric isomers

d. Tautomers

Ans. – a

58) A beam of light having a particular wavelength and having vibrations only in one plane is____

a. Ordinary light

b. Plane polarized light

c. Monochromatic light

d. None of above

Ans. – b

59) Optically active compound can rotate_____

a. Ordinary light

b. Plane polarized light

c. Monochromatic light

d. None of above

Ans. – b

60) Which instrument is used to measure angle of rotation?

a. Polarimeter

b. UV spectrometer



c. pH meter

d. Conductometer

Ans. – a

61) For being chiral compound, chemical compound should not possess following characteristic

a. Plane of symmetry

b. Centre of symmetry

c. Axis of symmetry

d. All of the above

Ans. – d

62) Followings are types of optical isomers except__

a. Enantiomers

b. Diasteromers

c. Conformers

d. Meso compounds

Ans. – c

63) How many possible stereoisomers for the compound CH3CH(OH)COOH.

a. 1

b. 2

c. 3

d. 4

Ans. – b

64) Which is the true option for Diastereomers?

a. They have only one chiral centre.

b. They have identical physical properties

c. They have two or more chiral centre.

d. All of the above.

Ans. – c

65) Ratio of dextro and levo isomers (d:l) of compound present in raceme mixture is__

a. 50:50

b. 40:60

c. 30:70

d. 20:80

Ans. – a

66) The process of separation of a racemic mixture into optically active d and l isomers is___



a. Racemization

b. Resolution

c. Both (a) and (b)

d. None of the above

Ans. – b

67) Absolute configuration of stereoisomer is denoted by__

a. R and S isomers

b. D and L isomers

c. d and l isomers

d. cis and trans isomers

Ans. – a

68) Relative configuration of stereoisomer is denoted by__

a. R and S isomers

b. D and L isomers

c. d and l isomers

d. cis and trans isomers

Ans. – b

69) The necessary conditions for geometric isomers are__

a. Presence of at least one double bond.

b. Each carbon atom of the double bond should be linked to two different atoms or groups.

c. Both (a) and (b)

d. None of the above.

Ans. – c

70) By studying which physical property, configuration of geometric isomers can be determined

a. Melting point

b. Solubility

c. Dipole moment

d. All of the above

Ans. – d

71) From the followings, which is true about conformational isomers?

a. Eclipsed conformation is more stable than staggered conformation.

b. Eclipsed conformation is less stable than staggered conformation.

c. Eclipsed conformation has low energy than staggered conformation.




Ans. – b

72) Most stable conformation of cyclohexane is___

a. Chair conformation

b. Boat conformation

c. Twist boat conformation

d. Half chair conformation

Ans. – a

73) The hydrogens lying in the plane of the cyclohexane ring are called____

a. Axial hydrogens

b. Chiral hydrogens

c. Equatorial hydrogens


Ans. – c

74) The hydrogens lying above or below the plane of the cyclohexane ring are called____

a. Axial hydrogens

b. Chiral hydrogens

c. Equatorial hydrogens


Ans. – a

75) Which is the true sentence for stereospecific reactions from the followings,

a. Reactants react at different rate i.e. they have different rate of reaction.

b. They give different stereoisomers as products.

c. They have different paths to give different types of compounds as products.

d. All of the above

Ans. – d

76) Which of the following statements most accurately describes the stereochemistry between the

various cyclohexanes?

a. Cis-1,2-dichlorocyclohexane and trans-1,2-dichlorocyclohexane rotate plane-polarized light in

opposite directions, and together in equal proportions form a racemic mixture.

b. The diaxial and diequatorial forms of trans-1,3-dichlorohexane can be separated by their

differing physical properties.

c. Only cis-1,4-dichlorocyclohexane is achiral due to a plane of symmetry, and cis-1,4-

dichlorocyclohexane is diastereomeric to trans-1,4-dichlorocyclohexane.



d. The conformational isomers of trans-1,2-dichlorocyclohexane are enantiomers, which are not

interconvertible, but resolvable.

Ans. – d

77) Which of the following is a mesocompound?

a. I

b. II

c. III

d. IV

Ans. – b

78) Which of the following is(are) not meso compound(s)?

a. II

b. II and III

c. I and III

d. I and II

Ans. – d

79) Which of the following is(are) not meso compound(s)?

a. I

b. II and III

c. I and III

d. I and II

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-meso-structures-q6.png





Ans. – a

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

a. A pair of stereoisomers each of which has two chirality centers

b. Any pair of stereoisomers

c. A pair of stereoisomers that are not mirror images of one another

d. A pair of stereoisomers that are non-superimposable mirror images of one another

Ans. – c

81) What is the relation between the given compound?

a. constitutional isomers

b. enantiomers

c. Diastereomers

d. Identical

Ans. – c

82) What is the relation between the given compounds?

a. Diastereomers

b. constitutional isomers

c. enantiomers

d. identical

Ans. – a

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-diastereomers-q7.png




83) What is the relation between the given compounds?

a. Diastereomers

b. constitutional isomers

c. enantiomers

d. identical

Ans. – a

84) Which of the following statements regarding enantiomers not true?

a. All (+) enantiomers are levorotatory

b. All (-) enantiomers rotate plane polarized light in a clockwise direction

c. (+) and (-) enantiomers rotate plane polarized light in opposite directions

d. All R enantiomers are dextrorotatory

Ans. – c

85) Which of the following is/are the S-enantiomer of alanine?

a. Only 1

b. Only 2

c. 1 and 3

d. 2 and 3

Ans. – c


https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-enantiomers-q2.png



86) Which of the following is the pair of enantiomer from the following substance?

a. I and II

b. II and III

c. III and IV

d. I and V

Ans. – a

87) Which of the following is capable of existing as a pair of enantiomers?

a. 2-methylpropane

b. 2-methylpentane

c. 3-methylpentane

d. 3-methylhexane

Ans. – d

88) Which statement about a chiral compound A is incorrect?

a. A racemate contains equal amounts of (+)-A and (–)-A

b. If A is resolved, it is separated into its enantiomers

c. (+)-A can also be labelled R-A, because (+) means the same as R

d. (+)-A and (–)-A will rotate polarized light equally but in opposite directions

Ans. – d

89) Which of the following is the definition of chirality?

a. The superimposability of an object on its mirror image

b. A molecule with a mirror image

c. The non-superimposability an object on its mirror image

d. A molecule that has a carbon atom with four different substituents

Ans. – d

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-enantiomers-q5.png



90) Which of the following compound(s) is/are chiral?

a. Both A and B

b. Only B

c. Only A

d. Neither A nor B

Ans. – a

91) Which symmetry element makes the given compound achiral?

a. Plane of symmetry (POS)

b. Center of symmetry (COS)

c. Axis of symmetry (AOS)

d. Alternating axis of symmetry (AAOS)

Ans. – a

92) Which of the following is the definition for enatiomerism?

a. A pair of stereoisomers each of which has two chirality centres

b. A pair of stereoisomers that are not mirror images of one another

c. A pair of stereoisomers that are non-superimposable mirror images of one another

d. Any pair of stereoisomers

Ans. – c

93) Which of the following notations is not used to distinguish between pairs of enantiomers?

a. R and S

b. E and Z

c. + and –

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-chirality-q5.png

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-chirality-q7.png



d. D and L

Ans. – b

94) Which among the following is not true about enantiomerism?

a. Assignments of R and S labels and (+) and (–) labels are not connected

b. The labels R and S refer to different conformers

c. The labels (+) and (–) are used to distinguish enantiomers

d. The specific rotation of enantiomers is equal and opposite

Ans. – b

95) Which of the following molecules does not possess enantiomers?

a. CH3CH2CH2CHBrCH3

b. CH3CH2CBr2CH3

c. CH3CHBrCH2CH3

d. CHBr2CH2CHBrCH3

Ans. – b

96) What does a polarimeter measure?

a. Polarity of the substance

b. Angle of rotation of an optical active compound

c. Concentration of the substance

d. pH of the substance

Ans. – b

97) A solution of 0.1 g/mL of a pure R enantiomer in a 1.0 dm (i.e., 10 cm) polarimeter rotates plane

polarized light by +4.8°. What is the rotation observed on this solution in a 2 dm polarimeter?

a. +2.4°

b. +4.8°

c. +19°

d. +9.6°

Ans. – d

98) . Polarimeter works on the principle of which of the following?

a. polarization of light

b. change of the electrical conductivity of solution with composition



c. change of angle of refraction with composition

d. change of electrical conductivity of solution with temperature

Ans. – a

99) Which of the following groups has the highest priority according to the Cahn-Ingold-Prelog

sequence rules?

a. CH3

b. CH2Cl

c. CH2OH

d. CHO

Ans. – d

100) What is the percent composition of a mixture of (S)-(+)-2-butanol, α= +13.52°, and (R)-(-

)-2-butanol, α = -13.52°, with a specific rotation α = +6.76°?

a. 75%(R) 25%(S)

b. 25%(R) 75%(S)

c. 50%(R) 50%(S)

d. 67%(R) 33%(S)

Ans. – a

101) What can be said with certainty if a compound has α= -9.25°?

a. The compound has the (S) configuration

b. The compound has the (R) configuration

c. The compound is not a meso form

d. The compound possesses only one stereogenic center

Ans. – c

102) Which of the following compounds can exhibit geometrical isomerism?

a. 1-Hexene

b. 2-Methyl-2-Pentene

c. 3-methyl-1-pentene

d. 2-Hexene

Ans. – d



103) How many stereoisomers are there for the following structure?

a. 1

b. 2

c. 3

d. 4

Ans. – c

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

a. 3

b. 1

c. 2

d. 4

Ans. – d

105) How many stereoisomers of 2,3-butanediol, CH3CH(OH)CH(OH)CH3, exist?

a. 3

b. 4

c. 1

d. 2

Ans. – a

106) How many number of stereoisomers possible for 2, 3-pentanediol?

a. 3

b. 4

c. 5

d. 6

Ans. – b

107) Which of the following is a not a five membered ring?

a. Pyridine

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-stereoisomers-q2.png



b. Pyrrole

c. Furan

d. Thiophene

Ans. – a

108) Which of the following five membered a ring is most resonance stabilized?

a. Furan

b. Thiophene

c. Pyrrole

d. Pyridine

Ans. – b

109) Five membered rings come under which category of heterocycle classification on the basis

of chemical behavior?

a. -excessive heterocycle

b. -deficient heterocycle

c. -equivalent heterocycle

d. Can’t say about the five membered rings

Ans. – a

110) Which is the most reactive five membered heterocyclic compound?

a. Pyrrole

b. Furan

c. Thiophene

d. Pyridine

Ans. – a

111) What is the product when thiophene reacts with Br2 in benzene?

a. 2-bromothiophene

b. 3-bromothiophene

c. 2,5-dibromothiophene

d. 3,4-dibromothiophene

Ans. – c

112) What is the product when pyrrole reacts with Br2 in ethanol?



a. 2,3-dibromopyrrole

b. 2,3,4,5-tetrabromopyrrole

c. 2,5-dibromopyrrole

d. 3,4-dibromopyrrole

Ans. – b

113) What is the name of the following reaction?

a. Gattermann reaction

b. Riemer tiemann reaction

c. Friedal craft reaction

d. Blanc’s chloromethylation

Ans. – b

114) What is the name of the following reaction?

a. Gattermann reaction

b. Riemer tiemann reaction

c. Friedal craft reaction

d. Blanc’s chloromethylation

Ans. – a

115) What will be the reagent used for the completion of the following reaction?

a. Concentrated acid

b. Dilute acid

https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-five-membered-rings-q8.png





c. Concentrated base

d. Dilute base

Ans. – b

116) Which heteroatom present in pyrrole?

a. Oxygen

b. Nitrogen

c. Silicon

d. Sulphur

Ans. – b

117) Which heteroatom present in Furan?

a. Oxygen

b. Nitrogen

c. Silicon

d. Sulphur

Ans. – a

118) Which heteroatom present in thiophene?

a. Nitrogen

b. Silicon

c. Oxygen

d. Sulphur

Ans. – d

119) Which compound is most basic?

a. Pyridine

b. Pyrrole

c. Imidazole

d. Pyrrolidine

Ans. – c

120) Which is least basic compound?

a. Pyridine

b. Pyrrole



c. Imidazole

d. Pyrrolidine

Ans. – b

121) Which of the following solvents is a heterocyclic compound?

a. DMSO

b. DMF

c. THF


Ans. – c

122) Which of the followings statements is correct?

a. Pyrrole has less aromatic character than furan

b. Pyridine is isoelectronic with benzene

c. Pyridine is tertiary amine

d. Pyrrole is strong base

Ans. – c

123) What is the correct order of reactivity (most reactive first) of pyrrole, furan and thiophene

towards electrophiles?

a. Furan > Pyrrole > Thiophene

b. Pyrrole > Furan > Thiophene

c. Furan > Thiophene > Pyrrole

d. Thiophene > Pyrrole > Furan

Ans. – b

124) Electrophilic substitution in furan usually occurs at:

a. Both the C2 and C3 atom

b. The O atom

c. The C2 atom

d. The C3 atom

Ans. – c

125) Nitration of pyrrole is best carried out using:

a. Acetyl nitrate



b. Ammonium nitrate

c. Concentrated nitric and sulphuric acid

d. Nitric acid

Ans. – a

126) If you wanted to form 2,3,4,5-tetrabromopyrrole from pyrrole, which of the following

conditions would be the best choice?

a. Br2 at 273K

b. Br2 at298 K

c. Br2 in the presence of radical initiator

d. Br2 in the presence of Lewis acid

Ans. – c

127) Which statement about thiophene is incorrect?

a. The S atom contributes two electrons to the n-system

b. Thiophene is polar

c. Thiophene is less reactive than pyrrole

d. Thiophene is more reactive than furan

Ans. – d

128) Pyrrole undergoes sulfonation in presence of _______to produce pyrrole – 2 – sulfonic

acid.

a. Conc. Sulphuric acid

b. SO3 and pyridine

c. Dilute sulphuric acid/pyridine

d. SO3 and ethanol

Ans. – b

129) Pyrrole undergoes iodination in presence of Iodine and potassium iodide to produce_____.

a. 2 – iodo pyrrole

b. 3 – iodo pyrrole

c. Tetra iodo pyrrole

d. Tri iodo pyrrole

Ans. – c



130) Oxidation of pyrrole in presence of chromium oxide (Cr2O3) and acetic acid

produce_______.

a. Maleinimide

b. Maleic acid

c. Pyrrole N-oxide


Ans. – a

131) Pyrrole is reduced by using Zn and acetic acid to get product_______

a. 2 – pyrroline

b. 3 – pyrroline

c. Pyrrolidine

d. All of the above

Ans. – b

132) Which product will be produced when pyrrole undergoes catalytic reduction in presence of

hydrogen gas and Ni metal?

a. 2 – pyrroline

b. 3 – pyrroline

c. Pyrrolidine

d. All of the above

Ans. – c

133) Identify the given heterocyclic compound.

a. Furan

b. Pyrazole

c. Pyrrole

d. Pyridine

Ans. – c



134) Pyrrole potassium on treatment with CO2 under pressure give mixture of 2 and 3 pyrrole –

carboxylic acid, identify the reaction.

a. Kolbe-Schmidt reaction

b. Reamer-Tiemann reaction

c. Gattermann Koch reaction

d. Coupling reaction

Ans. – a

135) Pyrrole is heated with_________ to open the ring and form succinaldehyde dioxime.

a. Concentrated sulphuric acid

b. Strong alkali with pyridine

c. Hydrogen cyanide with HCl

d. Ethanolic hydroxylamine hydrochloride

Ans. – d

136) Atorvastatin, drug useful in CVS disease, contain heterocyclic ring______.

a. Pyrazole

b. Pyrrole

c. Imidazole

d. Purine

Ans. – b

137) Bepridil, calcium channel blocker, contain heterocyclic ring_____

a. Pyrrole

b. Purine

c. Indole

d. Pyridine

Ans. – a

138) Ondansetron, anti emetic drug, contain heterocyclic ring______.

a. Thiophene

b. Pyrrole

c. Furan

d. Pyrimidine



Ans. – b

139) Which drug(s) possess pyrrole heterocyclic compound from the followings?

a. Captopril

b. Lincomycin

c. Triprolidine

d. All of the above

Ans. – d

140) Identify the following heterocyclic compound.

a. Furan

b. Thiophene

c. Oxazole

d. Thiazole

Ans. – a

141) Complete the following reaction.

a. Pyrrole

b. Furan

c. Indole

d. Oxazole

Ans. – b

142) Which would be the intermediate in the following reaction?



a. Furan – 2 carboxide

b. Furan- 2 – carbinol

c. Furoic acid


Ans. – c

143) Which would be the product when furan undergoes sulfonation in the presence of SO3 and

pyridine?

a. Furan – 2 – sulfolic acid

b. Furan – 3 – sulfonic acid

c. Mixture of (a) & (b)


Ans. – a

144) Which reagent is used for the nitration of furan?

a. Conc. Nitric acid and sulphuric acid

b. Acetyl nitrate

c. Nitrobenzene

d. Dilute nitric acid with benzene

Ans. – b

145) Friedel craft acetylation of furan by using acetic anhydride is carried out in the presence of

catalyst______.

a. AlCl3

b. FeCl3

c. BF3

d. LIAlH4

Ans. – c

146) Identify the reaction: when furan react with aryl diazonium chloride in the presence of

strong alkali to produce 2 – aryl furan.

a. Mercuration

b. Gattermann Koch reaction

c. Kolbe reaction

d. Gomberg reaction



Ans. – d

147) Bromination of furan by using Br2 will produce_________.

a. 2 – bromo furan

b. 3 – bromo furan

c. 2,5 – dibromo furan


Ans. – d

148) Identify the following reaction:

a. Cannizaro reaction

b. Benzoin condensation

c. Gomberg reaction

d. Mercuration

Ans. – a

149) Identify the following reaction:

a. Gomberg reaction

b. Reamer tiemann reaction

c. Benzoin condensation

d. Aldol condensation

Ans. – c

150) Complete the reaction:



a. Br2

b. HBr

c. KBr in alcohol

d. NaBr in pyridine

Ans. – a

151) Furan on treatment with acid undergoes protonation and form________.

a. Protonated furan

b. Polymeric product

c. Dihydro furan


Ans. – b

152) Oxidation of furan produces_________.

a. Furan oxide

b. Furfural

c. Furfuric acid

d. Succinaldehyde

Ans. – d

153) Catalytic reduction of furan gives______

a. 2,3 – dihydro furan

b. 2,5 – dihydro furan

c. Tetra hydro furan

d. 3,4 – dihydro furan

Ans. – c

154) Prazocin, sympatholytic drug contain__________heterocyclic ring.

a. Furan

b. Pyrrole

c. Oxazole

d. Indole

Ans. – a

155) Which drug of following does not contain furan ring?



a. Furazolidone

b. Lorpiprazole

c. Terazocin

d. Dantrolene

Ans. – b

156) Amiodarone, antiarrhythmic agent, possess_________ heterocyclic ring.

a. Pyridine

b. Furan

c. Thiophene

d. Purine

Ans. – b

157) From the followings, which drug contain furan heterocyclic ring?

a. Furazolidine

b. Nitrofurantoin

c. Fluticazone

d. All of the above

Ans. – d

158) Ranitidine, H2 receptor antagonist, possess________heterocyclic ring.

a. Acridine

b. Azepine

c. Pyridine

d. Furan

Ans. – d

159) Pilocarpine, cholinergic agonist, contains________heterocyclic ring.

a. Furan

b. Pyrrole

c. Thiophene

d. Purine

Ans. – a

160) Which heterocyclic ring is present in Diloxanide furoate, anti protozoal drug?



a. Acridine

b. Thiazole

c. Furan

d. Thiophene

Ans. – c

161) Which heterocyclic ring is present in Rofecoxib, NSAID?

a. Pyrrole

b. Furan

c. Purine

d. Indole

Ans. – b

162) Which is the following heterocyclic compound?

a. Thiophene

b. Thiazole

c. Furan

d. Pyrrole

Ans. – a


a. Thiazole

b. Oxazole

c. Thiphene

d. Furan

Ans. – c



164) What would be the product of following reaction?

a. Thiophene

b. Thiazole

c. Purine

d. Pyrimidine

Ans. – a

165) What would be the appropriate reaction condition for the following reaction;

a. SO2/AlCl3/673K

b. H2S/AlCl3/273K

c. H2S/Al2O3/673K

d. Sulphur/heat

Ans. – c

166) What is not true about thiophene from the following sentences?

a. Thiophene shows aromaticity.

b. Thiophene contains oxygen heteroatom.

c. Thiophene has diene like structure.

d. Thiophene has a flat pentagonal ring.

Ans. – b

167) Which is the true statement from followings?

a. Thiophene is more stable than pyrrole

b. Thiophene is more stable than furan

c. Both (a) & (b)


Ans. – c



168) Thiophene shows electrophilic substitution reactions mainly at position___.

a. C2

b. C3

c. C4

d. C5

Ans. – a

169) Which condition is appropriate for the nitration of thiophene?

a. Acetyl nitrate

b. Nitric acid +acetic anhydride

c. Concentrated nitric acid

d. Sodium nitrate

Ans. – b

170) Identify the reaction: When thiophene react with dimethyl formamide in the presence of

POCl3, it will produce thiophene – 2 – carboxaldehyde.

a. Kolbe reaction

b. Canizzaro reaction

c. Gattermann Koch reaction

d. Vilsmeir – Hoack reaction

Ans. – d

171) Sulfonation of thiophene can be carried out by using______________.

a. SO3 +Conc. HCl

b. Dilute Sulphuric acid

c. Concentrated Sulphuric acid

d. SO3 + HNO3

Ans. – c

172) Chloromethylation of thiophene is carried out with HCHO & HCl, it will

produce_______.

a. 2- chloromethyl thiophene

b. 2- methyl thiophene

c. 2- chloro thiophene

d. 2-chloro, 5- methyl thiophene



Ans. – a


a. Cl2

b. SO3 + HCl

c. Cl2 + HCl

d. SO2Cl2

Ans. – d

174) What will be the product of the following reaction?

a. 2- iodo thiophene

b. 2,5 – di iodo thiophene

c. 2,3 – di iodo thiophene

d. Tetra iodo thiophene

Ans. – a

175) What will be the product of the following reaction?

a. 5 – bromo thiophene

b. 3- bromo thiophene

c. 2 – bromo thiophene

d. 2,5 – di bromo thiophene



Ans. – c

176) Chlorination of thiophene by using Chlorine at 243K will form__________.

a. 2- chloro thiophene + 5- chloro thiophene

b. 2,5 – dichloro thiophene

c. 2- chloro thiophene + 2,5- dichloro thiophene

d. Tetra chloro thiophene

Ans. – c

177) Bromination of thiophene by using Bromine in benzene will produce________

a. 5 – bromo thiophene

b. 3- bromo thiophene

c. 2 – bromo thiophene

d. 2,5 – di bromo thiophene

Ans. – d

178) Identify the reaction:

a. Reimer Tiemann reaction

b. Canizzaro reaction

c. Vilsmeir – Hoack reaction

d. Benzoin condensation

Ans. – b

179) What would be the reducing agent for the following reduction of thiophene?

a. Na + ammonia

b. Hydrogen gas + Ni



c. Pd + ammonia

d. Pd + Hydrogen gas

Ans. – a

180) Thiophene on catalytic reduction with large amount of palladium (Pd) gives_________.

a. 2 – thiolen

b. 3 – thiolen

c. n – Butane

d. Tetra hydro thiophene

Ans. – d

181) Thiophene is reduced with Raney nickel (Ni) which results in removal of sulphur to

form______.

a. 2 – thiolen

b. 3 – thiolen

c. n – Butane

d. Tetra hydro thiophene

Ans. – c

182) Which drug(s) contain thiophene ring in its(their) structure?

a. Cephalothin

b. Cefoxitin

c. Temocillin

d. All of the above

Ans. – d

183) Which drug(s) contain thiophene ring in its(their) structure?

a. Tinoridine

b. Tiaprofenic

c. Tenoxicam

d. All of the above

Ans. – d

184) Thiophene & its derivatives show following pharmacological activity.

a. Sedative



b. Hypnotic

c. Anticonvulsant activity

d. All of the above

Ans. – d

185) Clotiazepam, CNS active agent, possess __________ heterocyclic ring.

a. Thiophene

b. Oxazole

c. Pyridine

d. Pyrrole

Ans. – a

186) Ticlopidine, anticoagulant activity, contain _________ heterocyclic compound.

a. Thiazole

b. Thiophene

c. Furan

d. Indole

Ans. – b

187) Which pharmacological effect is not produced by thiophene derivatives?

a. Anticoagulants

b. Diuretics

c. Coagulants

d. Anti asthmatics

Ans. – c

188) Thiophene probably undergoes to ___________ reaction.

a. Electrophilic substitution

b. Nucleophilic substitution

c. Electrophilic addition

d. Nucleophilic addition

Ans. – a

189) Furan probably undergoes to ___________ reaction.







Ans. – a

190) Pyrrole probably undergoes to ___________ reaction.





Ans. – a

semester iv pharmaceutical organic chemistry - iii

Documents