Remix education
Daily Pharma QuizpharmacyTopic wise MCQs

Pharmaceutical Organic Chemistry-III MCQs with Answers

PHARMACEUTICAL ORGANIC CHEMISTRY-III (BP401TT) MCQs with Answers

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. c

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?
a. This compound is chiral.
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?
a. This compound is chiral.
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 compoundd

screenshot 2021 04 26 20 51 30 477 com5902192921219313773 Pharmaceutical Organic Chemistry-III MCQs with Answers

a. 0
b. 1
c. 2
d. 3
Ans. – b

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

screenshot 2021 04 26 20 54 21 072 com5406473656448131975 Pharmaceutical Organic Chemistry-III MCQs with Answers

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?

screenshot 2021 04 26 20 55 46 477 com648900761103177615 Pharmaceutical Organic Chemistry-III MCQs with Answers

a. 0
b. 2
c. 4

d. 6
Ans. – d

37) How many enantiomers are there of the molecule shown belowd

screenshot 2021 04 26 20 57 45 585 com5760094558915827994 Pharmaceutical Organic Chemistry-III MCQs with Answers

a. 0
b. 2
c. 4
d.
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?

screenshot 2021 04 26 21 01 22 734 com7166016245054803479 Pharmaceutical Organic Chemistry-III MCQs with Answers

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?

screenshot 2021 04 26 21 02 11 666 com8195380834515597879 Pharmaceutical Organic Chemistry-III MCQs with Answers

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. Isopentand

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

Remix education

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

More Part link

➡️ Pharmaceutical Organic Chemistry-III MCQs with Answers :- Click here

➡️ Pharmaceutical Organic Chemistry-III (Part:-2) MCQs with Answers:- Click here

➡️ Pharmaceutical Organic Chemistry-III (Part:-3) MCQs with Answers :- Click here

➡️ Organic Chemistry-III (Part:-4) MCQs with Answers:- Click here

Subject:- Pharmaceutical Organic chemistry:- 3 MCQs with Answers

Topic:- (Chapter 1 & 2 – Stereochemistry)
(Chapter 3 – Heterocyclic compound – I)

Semester:- 4th sem sem 4

2 reviews

Shaikh Mateen July 4, 2021 at 9:58 am

How to download this MCQ

Mayuri Dhanaji Gurav July 18, 2021 at 10:34 am
Pharmaceutical organic chemistry

Leave a review