CHEMISTRY ISOMERISM

EXERCISE-I OBJECTIVE PROBLEMS (JEE MAIN)

1. The compounds C2H5OC2H5 and CH3OCH2CH2CH3 (B) Gauche, eclipse, anti
are (C) Eclipse, anti, gauche
(A) chain isomers (D) Anti, gauche, elipse
(B) geometrical isomers 9. How many primary amines are possible for the
(C) metamers formula C4H11N?

(D) conformational isomers (A) 2 (B) 3

2. C7H7Cl shows how many benzenoid aromatic (C) 4 (D) 5

isomers? 10. The R/S configuration of these compounds are
(A) 4 (B) 3 respectively.

(C) 5 (D) 6 HO
3. How many minimum no. of C-atoms are required H NH2
CF3
for position & geometrical isomerism in alkene? HS
COOH
(A) 4, 3 (B) 4, 4
(C) 3, 4 (D) 3, 3
4. How many structural formula are possible when H CH 3
one of the hydrogen is replaced by a chlorine CHO
atom in anthracene?
(A) 3 (B) 7
(C) 4 (D) 6 (A) R, R, S (B) R, S, R

5. Which of the following connot be written in an (C) R, S, S (D) S, S, S

isomeric form? 11. How many planes (pos) are presents in
(A) CH3 – CH(OH) – CH2 – CH3 Anthracene

(B) CH3 – CHO

(C) CH2 = CH – Cl
(D) Cl – CH2CH2 – Cl
6. The number of cis-trans isomer possible for the
following compound Anthracene
(A) 1 (B) 2
(C) 3 (D) 6
12.
(A) 2 (B) 4
(C) 6 (D) 8 CH3 Cl
7. The number of isomers of dibromoderivative of
an alkene (molear mass 186 g mol–1) is H Cl H Br

(A) 2 (B) 3
&
(C) 4 (D) 6 Br H H CH3
8. Increasing order of stability among the three COOH COOH
main conformation (i.e. eclipse, anti, gauche)
of ethylene glycol is : (A) Comformers (B) Diastereomers
(A) Eclipse, gauche, anti (C) Enantiomers (D) Position isomers

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ISOMERISM CHEMISTRY

13. Geometrical isomers can be O

(A) Diastereomers or Enantiomers
O H
(B) Structural isomers
(C) Inter convertable at room temprature. (C) (D)
(D) none of these H
H3C
14. Phenol and benzyl alcohol are
18. Which of the following structures represents a
(A) functional isomers chiral compound ?
(B) Homologous
CH3 CH3 CH3 CH3
(C) position isomers H H
(A) H C CH3
(B) H C CH3
(D) none of these 3 3
H OH H CH3
O OH O
CH3 CH3 CH3 CH3
S C CH C C CH3 H H3C
15. H
H H (C) (D)
H3C CH3 H3C CH3
HO OH H CH3

Number of chiral centers are: 19. Examine the compound on the right. How many
stereoisomers having this constitution are possible
(A) 1 (B) 2
?
(C) 3 (D) 4
CH3
16. Which of the follownig compounds is (S)–4- H3C
O
chloro-1-methylcyclohexene ? H3C
CH3
CH3 CH3
Br
CH3
CH3
(A) 2 (B) 4 (C) 6 (D) 8
(A) (B)
20. Which of the following heptanols are chiral 1-
heptanol, 2-heptanol, 3-heptanol, 4-heptanol.
Cl Cl
(A) All are chiral

CH3 CH3 (B) 2-heptanol and 3-heptanol

(C) 2-heptanol, 3-heptanol & 4-heptanol
(D) 3-heptanol and 4-heptanol
(C) (D)
21. Which of the following will exhibit geometrical
Cl Cl isomerism ?
(A) 1-phenyl-2-butene
17. Which of the following compounds has two
stereogenic centers (asymmetric carbons) ? (B) 3-phenyl-1-butene
Cl (C) 2-phenyl-1-butene
Cl Cl (D) 1, 1-diphenyl-1-propene

(A) (B)

Cl Cl

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CHEMISTRY ISOMERISM

CH3 Et CH3
H Cl
26. The compound with the above
22. (A) H OH (B) HO H HO H
C2H5
Et CH3 configuration is called.

Relation between given pair is (A) (2S, 3S)-2-chloro-3-hydroxypentane

(B) (2S, 3R)-2-chloro-3-hydroxypentane
(A) Enantiomer (B) Diastereomer
(C) (2R, 3R)-2-chloro-3-hydroxypentane
(C) Identical (D) Structural isomer (D) (2R, 3S)-2-chloro-3-hydroxypentane
23. Following eclipsed form of propane is repeated
after rotation of 27. H Cl H Cl

OH
O=–CH3 H Cl Cl H
The above compounds differ in
H
H (A) configuration (B) conformation
HH
(C) structure (D) chirality
(A) 45º (B) 90º 28. The compound C2H5OC2H5 and CH3OCH2CH2CH3
(C) 120º (D) 180º are
24. Stereoisomers differ from each other in what (A) enantiomers
respect ? (B) geometrical isomers
(A) Composition (B) constitution (C) metamers
(C) configuration (D) steric hindrance (D) conformational isomers
25. The number of isomers of C5H10 is 29. Which conformer of cyclohexane is chiral
(A) 10 (B) 11 (A) Chair (B) Boat
(C) 12 (D) 13 (C) Twisted boat (D) None of these
30. Minimum C atoms required for a compound to
show geometrical isomerism :
(A) 2 (B) 3
(C) 4 (D) None of these

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ISOMERISM CHEMISTRY

EXERCISE-II MULTIPLE CHOICE PROBLEMS (JEE ADVANCED)

1. A pure simple of 2-chlorobutane shows rotation 6. Which two of the following compounds are identical?
of PPL by 30º in standard conditions. When
OH
above sample is made impure by mixing its OH
opposite form, so that the composition of the OH
mixture become 87.5% d-form and 12.5% l-form, (I) (II)
then what will be the observed rotation for the O
O
OH
mixture. OH
OH OH OH
(A) –22.5º (B) +22.5º
(C) +7.5º (D) –7.5º HO OH OH
(III) (IV)
2. When an optically active compound is placed in
O O
a 10 dm tube is present 20 gm in a 200 ml OH
solution rotates the PPL by 30º. Calculate the (A) I & II (B) II & IV
angle of rotation & specific angle of rotation if
above solution diluted to 1 Litre. (C) III & IV (D) I & III

(A) 16º & 36º (B) 6º & 30º 7. Which two of the following compounds are
diasteromers ?
(C) 3º & 30º (D) 6º & 36º
OH
3. In the given following compound find out the
OH
pair of enantiomers and diastereomers OH
OH O (I) (II)
O
O
OH
OH
R R'
OH OH
OH
R
(A) 2, 2 (B) 2, 4 HO OH OH
(C) 4, 4 (D) 4, 2 (III) (IV)
O O
4. The molecule (s) that exist as meso structure(s) OH
(A) I & II (B) II & IV
(C) III & IV (D) I & III
8. Which of the following is properly classified as a
(K) (L) meso compound ?

H CH3
CH3
H OH HO
(A) (B) HO
(M) H
HO H CH3
CH3
(A) only M (B) both K and L
(C) only L (D) only K
C2H 5
5. Among the following, a pair of C2H5
r e so lvable configurational enantiomers is given H OH
by HO H
(A) cis-1, 2-dimethylcyclohexane (C) (D) H H
H OH
(B) cis-1, 3-dimethylcyclohexane H OH
(C) cis-1, 4-dimethylcyclohexane C2H5
CH 3
(D) trans-1, 3-dimethylcyclohexane

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CHEMISTRY ISOMERISM

9. Which two of the following compounds 13. How many stereoisomer are possible for the
represents a pair of enantiomers ? following molecule ?
Cl
HO OH
Br CH CH
(I) (II) CH3
HO OH

HO OH (A) 4 (B) 8
(C) 16 (D) 32
(III) (IV)
HO OH 14. How many stereoisomers are possible for the
following compound ?
(A) I & II (B) II & III
NO2 MeBrHC
(C) III & IV (D) II & IV
10. The drawing on the rigth shows that trans-1,
3-dichlorocyclohexane is chiral. Efforts to
resolve this compound fail. Why ?
Mirror
CH=CH-Me I
(A) 2 (B) 4
(C) 6 (D) 8
H Cl Cl H
CH3
Cl Cl
H H H Cl
15. Optical rotation produced by is 36°
Cl H
(A) the cis and trans isomers rapidly
interconvert. CH3
(B) the compound is actually a meso structure.
CH3
(C) the chair conformers rapidly interconvert
producing a recemic mixture. H Cl
then that product by is
(D) method for resolving alkyl chlorides are not H Cl
available. CH3
11. How many stereoisomers of (CH3)2CHCH =
CHCH2CH(OH)CH2Br are possible ? (A) –36° (B) 0°
(A) 2 (B) 3 (C) +36° (D) upredictable
(C) 4 (D) 5 OH
12. What common symmetry of elements if any are OH
found in the stable chair conformer of trans-1, 16. CH3 CH2 CH2 CH2 and CH3 C CH3 are
2-dichlorocyclohexane ?
(A) A single mirror plane and a C2 rotational CH3
axis.
(B) A single mirror plane & C3 rotational axis. (A) chain isomers (B) positional isomers
(C) both (D) none
(C) Two orthogonal mirror planes and a C2
rotational axis.
(D) A single C2 rotational axis but no mirror plane.

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ISOMERISM CHEMISTRY

17. Dextrorotatory -pinene has a specific rotaiton (A) they will have identical physical properties.
[]D20 = +51.3°. A sample of -pinene containing (B) they will have specific rotations of opposite
both the enantiomers was found to have a sign
(C) they will have identical chemical properties
specific rotationa value []D20 = +30.8°. The
(e.g. reactivity)
percentages of the (+) and (–) enantiomers
(D) they will have different physical properties.
present in the sample are, respectively.
23. How many stereoisomer may have this natural
(A) 70% and 30% (B) 80% and 20%
occuring compound.
(C) 20% and 80% (D) 60% and 40%
18. (+)-mandelic acid has a specific rotation of O
158°. What would be the observed specific HO CH2 OH
rotation of a mixture of 25% (–)-mandelic acid
and 75% (+)-mandelic acid ?
(A) +118.5° (B) –118.5° HO CH=CH–CH=CH–CH2–CH2–CH3
(C) –79° (D) +79° (A) 8 (B) 16
19. Number of structural isomers of compound having (C) 64 (D) 128
molecular formula C4H7Cl.
24. An optically pure compoud X gave an []D25 =
(A) 4 (B) 8 +20.0°. A mixture of X and its enantiomer Y
(C) 12 (D) 16 gave []D25 = +10°. The ratio of X to Y in the
20. Which of the following sugars has the mixture is
configuration (2S 3R, 4R) ? (A) 2 : 1 (B) 1 : 3
(C) 3 : 1 (D) 1 : 2
CHO CHO
25. Molecular formular C3H6Br2 can have (including
H OH H OH stereoisomers):
(A) H OH (B) HO H (A) Two gem dibromide
H OH H OH (B) One vic dibromide
CH2OH CH2OH (C) Two tertiary dibromo alkane
(D) Two secondary dibromo alkane
CHO CHO
26. Mesotartaric acid and d-tartaric acid are
HO H HO H
(A) positon isomers (B) enantiomers
(C) H OH (D) HO H
(C) diastereomers (D) racemic mixture
H OH H OH 27. The nubmer of isomers of C3H5Br3 (including
CH2OH CH2OH stereoisomers)
(A) 4 (B) 5
21. Which of the following statements must be true
(C) 6 (D) 7
for two pure chiral isomers ?
28. The number of optically active compounds in
(A) they must be enantiomers the isomers of C4H9Br is
(B) they must be diastereomers (A) 1 (B) 2
(C) they must be stereoisomers (C) 3 (D) 4
(D) they must be optically active 29. The prefered conformation of trans-1, 2-
dibromocyclohexane is:
22. Which of the following statements is true for a
pair of diastereomers ? (A) diaxial (B) diequatorial
(C) axial/equatorial (D) neither A, B nor C

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CHEMISTRY ISOMERISM

30. How many stereoisomers of the following Which of the above formula represent identical
molecule are possible? HOOC.CH=C=CH.COOH compounds ?
(A) Two optical isomers (A) I and II (B) I and IV
(B) Two geometrical isomers (C) II and IV (D) III and IV
(C) Two optical & two geometrical isomers
CO2H (II) CO2H CO2H
(D) None 34. (I) (III)
H OH H OH HO H
31. The structures shown here are related as being
H Br H OH HO H H OH
C H OH H OH H OH
CO2H CO2H CO2H
CH3 CH3
CO2H CO2H
C
HO H H OH
Br H
Br (IV) HO H (V) HO H
HO H HO H
H3C
C CO2H CO2H
H
which of the above compounds are in
enantiomers
H3 C
C H (A) II & III (B) III & IV
Br (C) III & V (D) I & V
(A) conformers (B) enantiomorphs 35. Which species exhibits a plane of symmetry ?
(C) geometrical isomers COOH
CH3 H
(D) diastereosiomers
32. Which of the following cannot be written in an H H H
isomeric form ? (A)
H CH3
(A) CH3 – CH(OH) – CH2 – CH3
H H
(B) CH3 – CHO
(C) CH2 = CH – Cl (D) Cl – CH2CH2 – Cl
(B)
CO2H CO2H CO2H
H OH H OH HO H OH H
33. (I) H OH (II) HO H (III) H OH H COOH
H OH H OH H OH H H
(C) H H
CO2H CO2H CO2H H
HOOC
CO2H H OH
CO2H
H OH Ph Ph
HO H
(IV) HO H (V) HO H
H H
HO H (D) H H
HO H
CO2H
CO2H COOH COOH

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ISOMERISM CHEMISTRY

36. Number of possible 3D-isomers (Stereoisomer) 39. The number of optically active isomers observed
of glucose are in 2,3-dichlorobutane is
(A) 10 (B) 14 (A) 0 (B) 2
(C) 16 (D) 20 (C) 3 (D) 4
37. Which of the following, compounds displays 40. How many total isomers are possible by replacing
geometrical isomerism ? one hydrogens atoms of propane with chlorine
(A) CH2 = CHBr (B) CH2 = CBr2 (A) 2 (B) 3
(C) ClCH = CHBr (D) Br2C = CCl2 (C) 4 (D) 5
38. Match List I with List II and select the correct 41. On chlorination of propane number of products
answer from the codes given below the lists: of the formula C3H6Cl2 is
List-I (A) 3 (B) 4
O (C) 5 (D) 6
(A) CH3 C O CH2 CH2 CH3 and 42. The two compounds given below are
O
D Cl
H3C CH2 C O CH2 CH3
H Br
I H
CH3 CH3 H Cl
D H
CH3
I Br
(B) and
(A) enantiomers (B) identical
CH3 (C) optically inactive (D) diastereosmers
43. Which of the following will not show optical
O OH isomerism.
(A) Cl – CH = C = C = CH – Cl
(C) and (B) Cl – CH = C = C = C = CH – Cl
O O HO OH COOH
CHO H (C) H OH
H OH
(D) H C OH and H3C C CHO COOH

CH3 OH
H
List II Cl H
(1) Enantiomer (2) Position isomers (D)
(3) Metamers (4) Tautomers
Me Cl
Codes:
(A) (B) (C) (D) Me

(A) 3 2 4 1
(B) 3 2 1 4
(C) 1 2 3 4
(D) 2 3 4 1

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CHEMISTRY ISOMERISM

44. Given compound show which type of isomerism? Cl Cl

O Cl Cl
S O (D)
and
Cl Cl
O
O 47. Sum of stereoisomer in the given compound (a)
and (b) are:
S O
Cl Cl = a (stereoisomer)
O
(A) Chain isomerism (B) Positional isomerism Cl
(C) Metamerism = b (stereoisomer) a + b = ?
Cl
(D) Functional group isomerism (A) 3 (B) 4
45. Shows which type of isomerism (C) 5 (D) 6
O Et
Keq.
Cl C O Et
H 48.
and
C C Me
Me
H CH3
equilibrium constant for above reaction is:
O
(A) K = 1 (B) K > 1
C O Cl (C) K < 1 (D) K = 0
H3C
C C Me
H H Me
(A) Functional group isomerism 49. H Incorrect statement about this
(B) Geometrical isomerism H
(C) Metamerism (D) Position isomerism compound is
46. Which of following pair is Diastereomers: (A) it shows geometrical isomerism
CO2H CO2H (B) it posses centre of symmetry
H OH (C) it posses plane of symmetry
H OH
(A) (D) it shows optical isomerism
HO H H OH
C2H5 CH3
CO2H CO2H H3C CH3 H C2H5
H CH3 50. (I) N (II) N
CH3
H H
H3C C Br C H H3C
(B) C C Br C C CH3 CH3
CH3 CH3
H H H
H3C CH3
CH3 Et
(III)
H OH HO H H H
(C)
H SH HS H N
H C2H5
Et CH3

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ISOMERISM CHEMISTRY

Which of the following statement is correct ? 57. The number of stereoisomers obtained by
(A) I & II are conformational isomers while II & bromination of trans-2-butene is :
III are functional isomers (A) 1 (B) 2
(B) I & II are functional isomers while II & III (C) 3 (D) 4
are conformational isomers 58. The number of stereoisomers obtained by
bromination of 1-butene is :
(C) I & II are functional isomers while I & III are
conformational isomers (A) 1 (B) 2
(C) 3 (D) 4
(D) None of these
59. isobutene + Br2  number of possible products
51. How many planes are presents in nepthalene
(A) 1 (B) 2
(C) 3 (D) 4
60. In which of the following molecule show chirality.
Me
Nepthalene (I)
COOMe
(A) 1 (B) 2
Me
(C) 3 (D) 6 (II) Cl
52. Total number of optically active alkyne possible
from molecular formula C3FClBrI (A) I is trans & chiral (B) II is trans & chiral
(C) I is cis & chiral (D) II is trans & achiral
(A) 2 (B) 4
61. Total number of stereoisomer is odd number for
(C) 6 (D) 8
53. Total number of geometrical isomer of given
compound will be (A) (B)

O O
CHO
CO2H
(A) 2 (B) 4 H OH
H OH
(C) 6 (D) 8 (C) (D)
H OH
H OH
54. H OH
CO2H
CH2–OH
Number of geometrical isomer of given compound
will be : Cl Cl
(A) 2 (B) 3 62. Statement-1 : C C C This compound
H H
(C) 4 (D) 5
will show geometrical isomerism.
55. The number of stereoisomers obtained by Statement-2 : Terminal carbon groups are
bromination of cis-2-butene is perpendicular to each other.
(A) 1 (B) 2 (A) Statement-1 is true, statement-2 is true
(C) 3 (D) 4 and statement-2 is correct explanation for
statement-1
56. The number of stereoisomers obtained by
reaction cis-2-butene with bromine in the (B) Statement-1 is true, statement-2 is true
presence of water is : and statement-2 is NOT correct explanation for
statement-1
(A) 1 (B) 2
(C) Statement-1 is true, statement-2 is false
(C) 3 (D) 4 (D) Statement-1 is false, statement-2 is true

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CHEMISTRY ISOMERISM

63. Which of the following compounds is optically 66. Which of the following statements is/are correct?
active ? (A) A meso compound has chiral centres but
exhibits no optical activity.
NO2 HO2C
(B) A meso compound has no chiral centres and
thus are optically inactive.
(A) (C) A meso compound has molecules which are
superimposable on their mirror images even
NO2 HO2C through they contain chiral centres.
(D) A meso compound is optically inactive
H3C H because the rotation caused by any molecule
(B) is cancelled by an equal and opposite rotation
H CO2H caused by another molecule that is the mirror
image of the first.
NO2 HO2C 67. Which of the following statements is/are not
correct D-(+) glyceraldehyde ?
(A) The symbol D indicates the dextrorotatory
(C) natures of the compound
CO2H O2N (B) The sign (+) indicates the dextrorotatory
nature of the compound
(C) The symbol D indicates that hydrogen atom
CO2H lies left to the chiral centre in the Fischer
H OH projection diagram.
(D) The symbol D indicates that hydrogen atom
HO H
(D) lies right to the chiral centre in the Fischer
H OH projection diagram.
CO2H 68. Which of the following compounds is optically
active ?
64. C4H6O2 does represent (A) 1-Bromobutane
(A) A diketone (B) 2-Bromobutane
(B) A compound with two aldehyde (C) 1-Bromo-2-methylpropane
(C) An alkenoic acid (D) 2-Bromo-2-methylpropane
(D) An alkanoic acid 69. Which of the following operations on the Fischer
CH3
65. Which of the following statement is/are not
correct?
(A) Metamerism belongs to the category of formula H OH does not change its
structural isomerism
(B) Tautomeric structures are the resonating
structures of a molecule C2H5
absolute configuration
(C) Keto form is always more stable than the (A) Exchanging groups across the horizontal
enol form bond
(D) Geometrical isomerism is shown only by (B) Exchanging groups across the vertical bond
alkenes. (C) Exchanging groups across the horizontal
bond and also across the vertical bond
(D) Exchanging a vertical and horizontal group.

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ISOMERISM CHEMISTRY

70. Which of the following combinations amongst

C H3
the four Fischer projections represents the same CH3
absolute configurations ?
(A) C
CH3 OH H

(I) H OH (II) H CH3 H3C

CH3
CH=CH2 CH=CH2 (B) C
CH3
H
CH=CH2
H3C
HO CH=CH2 CH3
(III) H3C OH (IV)
C
(C)
CH3
H H3C H
(A) II and III (B) I and IV
(C) II and IV (D) III and IV H3C
CH3
71. Which of the following statements for a meso
C
compound is/are correct ? (D)
H3C CH3
(A) The meso compound has either a plane or a
point of symmetry
74. Which of the following are correct represents
(B) The meso compound has at least one pair of L-amino acids
of similar stereocenters
(C) The meso compound is achiral COOH

(D) The meso comopound is formed when equal (A) H2N H

amounts of two enantiomers are mixed CH2OH
72. Which of the following compounds are optically
active ? NH 2
(A) CH3.CHOH.CH2CH3 C
(B) H
(B) H2C = CH . CH2.CH = CH2 COOH
HOH 2 C
H Cl
C C C
(C)
Cl H
NH2
COOH (C) C
O2N H2C
COOH
(D) H

HOOC OH
NO2 COOH
C
73. Which of the following will show optical isomerism H
(D) C NH 2
as well as geometrical isomerism.
H3C
H

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CHEMISTRY ISOMERISM

75. WHich of the following are D sugars. 78. Which of following compound having plane of
symmetry
CHO CHO
H OH CO2H
H OH H H
HO H H OH
HO H (A) (B)
(A) (B)
H OH H OH
H OH OH OH
H3C H CO2H
H CH2OH
OH OH
CH2 Br
OH CH2OH Cl H
OHC H C O (C) C C (D)
HO H HO H H Cl
(C) (D)
H OH H OH
79. Match the column:
HO CH2OH H OH
Column-I
H CH2OH
O OH
H
76. The Fischer projection of the molecule as
represented in the wedge edge. (A)
H
a CH3

d
c O
is
b H
X H
CH3
X X (B) H C
3 C

(A) d b (B) a b H2C

a d
CO2H
a X
H OH
(C)
(C) X b (D) b d H OH

d a CO2H

77. Given compound shows which type of isomerism

OH
H
HO
(D) CH2NH2

HO

and
Column-II
(P) Total number of stereoisomers isodd for
structure
(A) Chain isomerism
(Q) Total nubmer of streiosmers is even for the
(B) Positional isomerism structure
(C) Constitutional isomerism (R) Odd number of chiral centrec
(D) None (S) Even number of chiral centre

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ISOMERISM CHEMISTRY

80. Match the column:

Cl Cl
Column-I
Me COCH2CH2COOH (C)
N
Me Me
Cl Cl Cl Cl
(A)
Br
Me Cl Cl
Me COCH2CH2COOH Cl
N
Me Me (D) Cl
(B) Cl Cl
Br Br
Me Column-II

Cl (P) Position isomers

(Q) Enantiomers
(C) Me – CH – CH = C = CHCl
(R) Diastereomers
H
(S) Identical
Me 82. Match the column :
(D) Column-I
H
Me Cl O
Column-II
(A)
(P) Show optical isomerism Me
(Q) Show geometrical isomerism
(R) resolvable Me Cl
(S) non-resolvable
81. Match the column:
Column-I Br

Cl Cl (B)
Br
Cl Cl
H Cl
(A) C
(C)
C
Cl Cl Cl H
Cl Cl
COOH
Cl
H OH
(D)
(B) HO H
Cl Cl
COOH
Cl

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CHEMISTRY ISOMERISM

Column-II A structure with a plane of symmetry is achiral

(P) Total number of stereo isomers are odd. and superimposable on its mirror image and
cannot exist as two enantiomer. A structure
(Q) Total number of stereocentres are even without a plane of symmetry is chiral and not
or have centre of symmetry superimposable on its mirror image and can exist
(R) Compounds havings plane of symmetry as two enantiomer.
or axis of symmetry
(S) Compounds have zero dipole in given form. CH3
83. Match the column : H Br
Column-I
84. H Cl
CH3 H H F
H CH2OH and H3C CH2NH2
(A) CH3
NH2 OH
Number of enantiomeric pairs are
CH3 Cl (A) 2 (B) 4
H Cl and H CH3
(B) (C) 8 (D) 10
Et Et
85. (a) Cl (b) Cl
CH3 H
H OH and H 3C Et
(C)
Et OH
Cl Cl Cl Cl
H5C2 H5C2
and Relation between (a) & (b) is
(D)
HO H H OH
(A) Enantiomer (B) Diastereomer
Column-II (C) Identical (D) Structural isomer
(P) Structural isomer 86. Compound has both center of symmetry and
(Q) Identical P.O.S
(E) Enantiomers
Cl
(S) Diastereomers Cl Cl

Cl
(A) (B)
Paragraph for Questions Nos. 84 to 86
If a molecule contains one carbon atom carrying Cl Cl
four different groups it will not have a plane of
symmetry and must therefore be chiral. A carbon
atom carrying four different groups is a
steregoenic or chiral centre.
(C) (D)

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ISOMERISM CHEMISTRY

EXERCISE-III (JEE ADVANCED)

1. What kind of reagent would be needed to resolve 4. Classify each of the following pairs of structure
a recemic amine, such as 2-aminobutane? as
(A) the pure optically active amine to serve as I. Identical E. Enantiomers.
a template forcrystallization. D. Diastereomers
(B) an achiral carboxylic acid to give a recemic CH = O CH = O
mixture of amine salts.
(C) an enantiomerically pure chiral carboylic acid H OH HO H
(a)
to give a diastereomeric mixture of amine salts.
CH3 CH3
(D) a recemic chiral carboxylic acid to give a CH = O CH = O
complete mixture of isomeric amine salts.
2. Determine if the following pairs are identical, H OH HO H
isomers, enantiomers, or diastereomers. (b) H OH H OH
OH
OH HO
(i)
OH
_____ CH3 CH3
Br Br
HO Br Br Br Br
(c) & Br
OH Br
(ii) ______
5. Classify each of the following pairs of structure
(a)-(e) as:
CHO CH2OH
I. Identical E. Enantiomers.
H OH HO H
D. Diastereomers
(iii) H OH HO H _____________
CH3 CH3
CH2OH CHO
3. Determine if the following pairs are identical, (a) H Br & Br H
isomers, enantiomers, or diastereomers.
HO CH2CH3 CH2CH3
H OH
NH2 H
H2N
(i) HO ____ CH3 CH2CH3
COOH
L-DOPA HOOC OH
H Cl
CH2OH CH2OH (b) &H CH3
H OH H OH CH2CH3 Cl
H CH3 H3C H
CH3 CH3
(ii) _____________
H Br H Br
(c) &
H Br Br H
CH3 CH3

CH3 CH3
(iii) _________ H Br Br H
(d) &
H Br Br H

CH3 CH3

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CHEMISTRY ISOMERISM

O O
Br Br
Br Br CH3 CH3
(c) ______
(e) &
Br Br H3C H3C
O O
6. State the relationship between each of the CH3 H3C CH3
following five (5) pairs of structures (identical,
enantiomers, diastereomers, structural isomers, (d) ______
different compounds that are not isomeric) H3C
OH OH O O
H H
CH3 H3C
(a) CH3 CH3_______
(e) ______
H3C CH3
OH OH CH3
H H 8. Select chiral molecule out of the following list
CH3
compound
(b) _______
CH3

(i)
OH OH
H H
O
(c) CH3 CH3______
H
HOOC OH
OH OH
H H HO H
(ii)
(d) CH3 CH3______ HO H
COOH
OH OH
H H
CH3 CH3______ C C C
(e)
(iii)

7. State the relationship between each of the

following five (5) pairs of structures (identical,
enantiomers, diastereomers, structural isomers,
conformational isomers, different compounds O
that are not isomeric)
C C6H5
O O
CH3 CH3
N
(iv) H
(a) _______ N
HO2C
H3C H3C
CO2H
O O
CH3 (v) N N
CH3
HO2C
(b) ______
H3C (Azodiformic acid)
H3C

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ISOMERISM CHEMISTRY

9. Discuss the optical activity of the following two CH3

compounds and also lable them as polar and (a) enantiomers
non polar.
Br H
diastereomers
Cl Cl identical none of these
H H H3C H
(I)

(b) HO enantiomers
Cl H
H Cl diastereomers
(II) identical none of these
CH3

10. (18) Now for some questions about

stereochemical relationships. (c) enantiomers

Column A Circle the word (s) in this column CH3

diastereomers
that describe the molecules in column A. identical none of these
OH
Br
(A) chiral achiral
HO OH

H3C (d) enantiomers

H
meso none of these diastereomers
identical none of these
H3C H
(B) chiral achiral 11. A cyclobutandicarboxylic acid exist in two
stereo-isomeric forms in which one is polar but
OH
non-resolvable while other is non-polar but
resolvable into enantiomers. Deduce structures
of all these compounds.
meso none of these
12. How many isomers are possible for nitrophenol?
CH3 13. A compound with molecular formula C4H10O, can
show metamerism, functional isomerism and
(C) chiral achiral positional isomerism. Justify the statement.

CH3 14. Calculate the total number of stereoisomers in

the following compounds.
meso none of these
CHO H H
OH
CHOH
HO OH (I) (II) HOOC COOH
(D) chiral a chiral CHOH
CH2OH

meso none of these C OO H

Column-B Circle one word in this colum C HO H
that best describes the relationship of the
molecules in columns A and B (III) C HO H
C HO H
C OO H

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CHEMISTRY ISOMERISM

15. In what stereoisomeric forms would you expect Ph

the following compounds to exist ?
(a) EtCH(CO2H)Me (b) MeCH(CO2Et)CO2H
Me
(V) (VI) S O
(c) Ph
O CO2H
17. Considering rotation about the C-3 – C-4 bond
(d) of 2-methylhexane
(a) Draw the Newman projection of the most stable
H H
confomrer
(e) C C C C (b) Draw the Newman projection of the least stable
H H confomrer
(f) Et(Me)C=C=C(Me)Et 18. Determine whether each of the following
Ph CO2H compounds is a cis isomer or a trans isomer.
H H
(g)
(a) Br Cl
Ph CO2H

I Br

H3C H
(h) (i) (b)

H
Br
H Cl H

H
(c) CH3
(j) (k)
Br
H
H
O
Br
H H CH3
(d)
(e) C C C C
H
H H
H
16. With reasons, state whether each of the
following compounds I to VII is chiral.
Cl
CH3
Cl Cl (e)

H H H
(I) (II)
Cl H
H
H Cl CH3 CH3
Cl CO2H (f)
O O
(III) C C C (IV) H
Cl Me

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ISOMERISM CHEMISTRY

19. An object that has no element of symmetry is 30. How many steroisomers exist for
called what? (a) 3-methylcyclopentanol?
(A) Tetrahedral (B) achiral (b) 1,3-Cyclohexanediol?
(C) symmetric (D) asymmetric 31. Total steroisomers of a given compound are ?
20. Draw all the possible stereoisomers of 3- Me
pentene-2-ol.
H CH=CH=CH-Me
21. Draw optically active stereo isomer of the (a) H D
following compound.
CH=CH-Me
Cl CH=CH-Me
NO 2
Cl Cl
(b)
Cl Cl
COOH Me
Cl
32. Mark each chiral center in the following molecules
22. Calculate the number of aromatic 1º-amine with an esterisk. How many stereoisomers are
possible for each molecule?
CH3
NH2 CH2–COOH
isomers possible of toluidine CH3CHCHCOOH
CH–COOH
(a) (b)
OH OH
HO–CH–COOH
23. Calculate the number of aromatic isomeric
amides possible of acetanilide OH
O
(c) (d)
NH–C–CH3

O OH
24. Calculate the number of isomeric ethers possible (e) (f)
O COOH
OH
OH

of
(g)
25. How many pair(s) of geometrical isomers are O
possible with C5H10(only in open chain structues) 33. (a) Label the four chiral ceners in amoxicillin,
which belongs to the family of semisynthetic
26. Total number of compounds with molecular
penicillins.
formula C 5H 10 which can show geometrical
isomerism are (only cyclic)? O
27. How many enatiomers are possibe on
monochlorination of isopentane. HO CH–C–HN S
CH3
28. Find out the total number of cyclic isomers of NH2 N CH3
C5H10 which are optically active? O
C
29. Calculate the total number of open chain HO O
isomeric compounds of molecular formula C4H8O
Amoxicillin
which can show geometrical isomerism.

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CHEMISTRY ISOMERISM

(b) Mevacor is used clinically to lower serum 36. Which of the following compounds are chiral ?
chloesterol levels. How many chirality centers Which, if any, are meso ?
does Mevacor have?

HO O

O
O
(a) (b)
O
CH3
CH3

H3C
Mevacor (c) (d)

34. Among the following How many compounds are 37. Among of the following how many are meso com-
chiral ? pounds ?

CH3 Br Br Br H
CH3
C C C C
(a) (b) (i) H H (ii) H
CH3 CH3 Br
CH3 CH3 CH3 CH3
CH3
CH3
HO OH
CH3
(c) (d) (iii) (iv)
CH3 CH3 OH OH
CH3
CH3 Cl CH3 Cl CH2OH
CH3
(e) (f) HO H OH
CH3 Cl CH3 (v) (vi) H OH
Cl CH3 CH3 Cl OH CH2OH

(g) (h) CHO CH2OH

CH3 Cl Cl CH3 H OH HO H
35. Are the following structures chiral as drawn ?
When placed in a solution at 298 K, which
structure will show an optical rotation? Explain. (vii) (viii)
H OH H OH
CH2OH CH2OH

CH2OH
(a) (b) H OH

(ix)
(c) (d) H OH
CH2OH

(e) (f)

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ISOMERISM CHEMISTRY

38. Among the following compounds how many has 41. Following are four Newman projection formulas
a stereoisomer that is a meso compound ? for tartaric acid.
(a) (i) 2,3-dimethylbutane COOH COOH
(ii) 2-bromo-3-methylpentane H OH HO H
(iii)1-bromo-2-methylcyclohexane
(b) (i) 3,4-dimethylhexane
(ii) 3,4-diethylhexane H OH H OH
(c) (i) 1,3-dimethylcyclohexane COOH COOH

(ii) 1,4-dimethylcyclohexane (1) (2)

(iii) 1,2-dimethylcyclohexane COOH COOH
39. How many compounds among the following have
a stereoisomer that is achiral ? HOOC OH H COOH

(a) (i) 2,3-dichlorobutane

(ii) 2,3-dichloropentane
HO H HO H
(iii) 2,3-dichloro-2,3-dimethylbutane
(b) (i) 1,2-dimethylcyclobutane H OH
(ii) 1,3-dibromocyclobutane
(3) (4)
(iii) 1,3-dichlorocyclopentane
(iv) 1,2-dimethylcyclopentane (a) Which represent the same compound ?
(c) (i) 2,4-dibromopentane (b) Which represent enantiomers ?
(ii) 2,3-dibromopentane (c) Which represent a meso compound ?
(iii) 1,4-dimethylcyclohexane (d) Which are diastereomers ?
40. Are the formulas within each set identical, enan- 42. Following are stereorepresentations for the
tiomers, or diastereomers ? three stereoisomers of 2,3-butanediol. The car-
bons are numbered beginning from the left, as
Cl H H Cl shown in (1).
HO H HO H
(A) and
4
H OH HO H 1 2 3

H OH HO H
H Cl HO H
(1) (2)
(B) and H OH
H OH H Cl

H Cl HO H HO H

(3)
(C) and
(a) Assign an R or S configuration to each chiral
HO H Cl H center.
(b) Which are enantiomers ?
(c) Which is the meso compound ?
(d) Which are diastereomers ?

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CHEMISTRY ISOMERISM

43. Find out the total number of major products

(including stereoisomers) are obtained in each
of the following reactions. (ii) Br2
  x
CH2Cl2
(i) (a) 1-butene + HCl x CH3 CH3
(ii) 1-butene + HBr + peroxide y
Find the value of (x + y) ?
(b)  y
H2

H3C CH3 Pt
CH3 CH2CH3
(ii) (a) C C + HBr x
H3C H 45. Find out the total number of major products
(including stereoisomers) are obtained in each
H3C CH3 of the following reactions.

(b) C C peroxide
 HBr    y CH3CH2 CH3
H3C H
(i) (a) C C H2
 x
Pt
(iii) (a) CH3CH2CH2CH = CH2 + HCl x CH3 CH2CH3
H H
CH3CH2 CH2CH3
(b) C C
(b) C C
CH3CH2 CH2CH3  y
H2

CH3 CH3 Pt


H
 H2O  y
H3C CH3
(c) C C Pt
+H2  z
H3C CH2CH2CH3
(c) + HBr z
H3C Find the value of (x + y + z) ?

Find the value of (x + y + z) ?

44. Find out the total number of major products (ii) (a) H2
 x
(including stereoisomers) are obtained in each CH3 CH3
Pt

of the following reactions.

(i) (a) cis-3-heptene+Br2 x
(b) trans-3-heptene + Br2 y Br2
(b)   y
(c) trans-3-hexene + Br2 z CH3 CH2CH3
CH2Cl2

Find the value of (x + y + z) ?

find the value of (x+y)?

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ISOMERISM CHEMISTRY

EXERCISE-IV PREVIOUS YEAR QUESTIONS LEVEL-I (JEE MAIN)

Q.1 Stereo - Isomerism includes - [AIEEE-2002] Q.7 Which of the following compounds is not
(A) Geometrical isomerism only chiral ? [AIEEE-2004]

(B) Optical isomerism only (A) 1 – chloropentane

(C) Both geometrical & optical isomerism (B) 2 – chloropentane

(D) Position & Functional isomerism (C) 1 – chloro –2–methyl pentane
Q.2 Which of the follow ing does not show (D) 3 – chloro – 2 – methyl pentane
geometrical isomerism - [AIEEE-2002] Q.8 Which of the following will have a mesoisomer
(A) CH3 – CH = CH – CH3 also - [AIEEE-2004]
(B) CH3 – CH2 – HC = CH2 (A) 2 - Chlorobutane
(C) CH3 – C  CH – CH3 (B) 2, 3 - Dichlorobutane
|
Cl (C) 2,3 - Dichloropentane
(D) ClHC = CH – CH2 – CH3 (D) 2-Hydroxypropanoic acid
Q.3 Racemic mixture is formed by mixing two – Q.9 Which types of isomerism is shown by 2,3–
[AIEEE-2002] dichlorobutane ? [AIEEE-2005]
(A) Isomeric compounds (A) Optical (B) Diastereo
(B) Chiral compounds (C) Structural (D) Geometric
(C) Meso compounds Q.10 Increasing order of stability among the three
(D) Enanitiomers with chiral carbon main conformations (i.e. Eclipse, Anti, Gauche)
Q.4 Geometrical isomerism is not shown by – of 2-fluoroethanol is [AIEEE 2006]
[AIEEE-2002] (A) Gauche, Eclipse, Anti
(A) 1, 1– dichloro–1–pentene (B) Eclipse, Anti, Gauche
(B) 1, 2– dichloro–1–pentene (C) Anti, Gauche, Eclipse
(C) 1, 3– dichloro–2–pentene
(D) Eclipse, Gauche, Anti
(D) 1, 4– dichloro–2–pentene
Q.11Which of the following molecules is expected
Q.5 Racemic mixture is – [AIEEE-2002] to rotate the plane of plane-polarised light?
(A) A mixture of chiral carbons
[AIEEE-2007]
(B) A mixture of isomers
(C) A mixture of aldehydes and ketones
(D) A mixture of alcohols and ethers
(A) (B)
Q.6 Among the following four structures I to IV

(i) (ii) COOH

H2N H
(iii) (iv) (C) (D)
H
It is true that – [AIEEE-2003]
Q.12 Which one of the following conformations
(A) Only (iii) is a chiral compound of cyclohexane is chiral ? [AIEEE-2007]
(B) Only (ii) and (iv) are chiral compounds (A) Twist boat (B) Rigid
(C) All four are chiral compounds (C) Chair (D) Boat
(D) Only (i) and (ii) are chiral compounds

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CHEMISTRY ISOMERISM

Q.13 The absolute configuration of Q.15 The number of stereoisomers possible for a
compound of the molecular formula
HO2C CO2H
CH3–CH=CH–CH(OH) –Me is : [AIEEE-2009]

is (A) 3 (B) 2
OH (C) 4 (D) 6
HO H H
Q.16 Out of the following, the alkene that exhibits
[AIEEE-2008]
optical isomerism is [AIEEE-2010]
(A) R, R (B) R, S
(A) 3–methyl–2–pentene
(C) S, R (D) S, S
(B) 4–methyl–1–pentene
Q.14 The alkene that exhibits geometrical isomerism
(C) 3–methyl–1–pentene
is : [AIEEE-2009]
(A) propene (D) 2–methyl–2–pentene

(B) 2-methyl propene Q.17 How many chiral compounds are possible on
monochlorination of 2–methyl butane?
(C) 2-butene
(A) 4 (B) 6 [AIEEE-2012]
(D) 2- methyl -2- butene
(C) 8 (D) 2

LEVEL-II (JEE ADVANCED)

1. The number of isomers for the compound with
molecular formular C2BrClFI is 4. (i) µobs = µ x
i
i i

[JEE 2001(Scr.)]
whre µ i is the dipole moment of a stable
(A) 3 (B) 4 conformer of the molcule, Z – CH2 – CH2 – Z and
(C) 5 (D) 6 xi is the mole fraction of the stable conformer.
2. Which of the following compounds exshibits Given : µobs = 1.0 D and x (Anti) = 0.82
stereoisomerism ? [JEE 2002(Scr.)] Draw all the stable conformers of Z – CH2 – CH2
– Z and calculate the value of µ(Gauche).
(A) 2-methylbutene-1
(ii) Draw the stable conformer of Y – CHD – CHD
(B) 3-methylbutyne-1 – Y (meso form), when Y = CH3 (rotation about
(C) 3-methylbutanoic acid C2 – C3) and Y = OH (rotation about C1 – C2) in
(D) 2-methylbutanoic acid Newmann projection. [JEE 2005]
5. The number of structural isomers for C6H14 is
3. In the given conformation, if C2 is rotated about
[JEE 2007]
C2 – C3 bond anticlockwise by an angle of 120°
(A) 3 (B) 4
then the conformational obtained is
(C) 5 (D) 6
[JEE 2004(Scr.)] 6. Statement-1: Molecules that are not
4 superimposable on their mirror images are chiral.
CH3 because
H H Statement-2: All chiral moleculs have chiral
3
centres. [JEE 2007]
2 (A) Statement-1 is true, statement-2 is true and
statement-2 is correct explanation for
H H
statement-1
1
CH3 (B) Statement-1 is true, statement-2 is true and
(A) fully eclisped conformation statement-2 is NOT correct explanation for
(B) partially eclipsed conformation statement-1
(C) Statement-1 is true, statement-2 is false
(C) gauche conformation
(D) staggered conformation (D) Statement-1 is false, statement-2 is true

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ISOMERISM CHEMISTRY

7. The correct statement(s) about the compuond (D) If the stereochemistry about the double bond
given below is (are) [JEE 2008] in X is cis, the number of enantiomers possible
for X is 2.
Cl H 10. The total number of cyclic structural as well as
stereo isomers possible for compound with the
H3C molecular formular C5H10 is [JEE 2009]
CH3
11. The total number of cyclic isomers possible for
Cl H a hydrocarbon with the molecular formula C4H6
is [JEE 2010]
(A) The compound is optically active
12. I n the Newman projection for 2, 2-
(B) The compound possesses centre of
dimethylbutane [JEE 2010]
symmetry
(C) The compound possesses plane of symmetry
X
(D) The compound possesses axis of symmetry
H3C CH3
8. The correct statement(s) concerning the
structures E, F and G is (are) [JEE 2008]

O H H
H3C
Y
(E)
H3C CH3 X and Y cn respectively be
(A) H and H (B) H and C2H5
H3C OH
(C) C2H5 and H (D) CH3 and CH3
(F) 13. Amongst the given options, the compound(s) in
H3C CH3 which all the atoms are in one plane in all the
possible conformations (in any), is (are)
CH3 [JEE 2011]
H3C

(G) H H
H3C OH C C
(A)
(A) E, F and G resonance structures H2C CH2
(B) E, F and E, G are tautomers
(C) F and G are geometrical isomers H

(D) F and G are diastereomers H C C C

(B)
9. The correct statement(s) about the compound CH2
H3C(OH)HC – CH = CH – CH (OH)CH3(X) is (are)
(C) H2C = C = O
[JEE 2009]
(D) H2C = C = CH2
(A) The total numbre of stereoisomers possible
for X is 6 14. In Allene (C3H4), the type (s) of hybridisation
of the carbon atoms is (are) [JEE 2012]
(B) The total number of diastereomers possible
for X is 3 (A) sp and sp3 (B) sp and sp2
(C) If the stereochemistry about the double bond (C) only sp2 (D) sp2 and sp3
in X is trans, the number of enantiomers possible
for X is 4.

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CHEMISTRY ISOMERISM

15. The number of optically active product obtained 17. Which of the given statement(s) about N, O, P
from the complete ozonolysis of the given and Q with respect to M is (are) correct?
compound is [JEE 2012] [JEE 2012]

CH3 H
Cl
CH3–CH=CH–C–CH=CH–C–CH=CH–CH3 HO H HO H H
OH
H HO Cl H CH3 HO
CH3
H OH H
CH3 Cl CH3
(A) 0 (B) 1
(C) 2 (D) 4 M N O

16. Which of the following molecules in pure from is

(are) unstable at room temperature [JEE 2012]
CH3 CH3
H OH HO H
(A) (B)

HO H HO H
O O Cl Cl
P Q
(C) (D)
(A) M and N are non-mirror image stereoisomers
(B) M and O are identical
(C) M and P are enantiomers
(D) M and Q are identical

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ISOMERISM CHEMISTRY

ANSWER-KEY
EXERCISE-I OBJECTIVE PROBLEMS (JEE MAIN)

1. C 2. A 3. B 4. A 5. C 6. A 7. B
8. C 9. C 10. A 11. C 12. D 13. A 14. D
15. B 16. A 17. D 18. D 19. D 20. B 21. A
22. C 23. C 24. C 25. D 26. A 27. C 28. C
29. C 30. D

EXERCISE-II MULTIPLE CHOICE PROBLEMS (JEE ADVANCED)

1. B 2. B 3. B 4. B 5. D 6. B 7. D
8. A 9. C 10. C 11. C 12. D 13. C 14. D
15. B 16. A 17. B 18. D 19. C 20. C 21. D
22. D 23. C 24. C 25. A 26. C 27. C 28. B
29. B 30. A 31. D 32. C 33. B 34. C 35. D
36. C 37. C 38. A 39. B 40. A 41. C 42. A
43. A 44. C 45. C 46. B 47. C 48. B 49. B
50. D 51. C 52. D 53. B 54. C 55. B 56. B
57. A 58. B 59. A 60. AD 61. ABC 62. D 63. BC
64. ABC 65. BCD 66. AC 67. AD 68. B 69. C 70. C
71. ABC 72. ACD 73. ACD 74. ACD 75. ACD 76. AC 77. BC
78. ABCD 79. (A) Q, S; (B) Q, S; (C) P, S; (D) Q, R 80. (A) P, R; (B) S; (C) P, R; (D) P, Q, S
81. (A) R, (B) P, (C) S, (D) S 82. (A) P, Q, R (B) Q, R, S (C) Q, R, S (D) P, Q, R
83. A P; B R; C Q; D R 84. B 85. B 86. D

EXERCISE-III (JEE ADVANCED)

1. c

2. (I) Diasteromers (ii) Enantiomers (iii) Identical

3. (I) Identical (ii) Diastereomers (iii) Diastereomers

4. (a) E (b) D (c) I

5. (a) E (b) I (c) D (d) I (e) E

6. (a) Diastereomers (b) diastereomers(c) not isomer (d) structural (e) Enantiomer

7. (a) Dia (b) Not isomer(c) Enenatiomers (d) Structural isomers (e) Identical
8. (i) achiral, (ii) achiral, (iii) Chiral, (vi) Chiral, (v) achiral

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CHEMISTRY ISOMERISM

9. Compound I is optically inactive since it contain a plane of symmetry. Compound II is enantiomeric

since it does not contain plane of symmetry. Hence chiral. Also compound I is polar while II non
polar.
10. (A) Column (a) Chiral (b) chiral (c) meso (d) chiral
(B) Column (a) enantiomers (b) enantiomers (c) diastereomers (d) diastereomers
11. The compound must be 1, 2-cyclobutan-dicarboxylic acid since all other constitutional isomerers
are non-resovable.

COOH COOH

Polar but non-resolvable H H Non-polar

HOOC H

COOH
H
due to plane of but resolvable
symmetry
(cis-isomer) (trans-isomer)
12. 3

13. (i) Et –O – Et, (ii) CH3 – O – CH2 – CH2 – CH3 (iii) CH3 – CH2 – CH2 – CH2 – OH, (iv) CH3 CH2 CH CH3
OH
I and II metamers, I & III functional isomers, III & IV position isomers.

14. (I) 4, (II) 3, (III) 4

15. Optical : a, b, c, d, f, g, i, k; Geometrical isomer : c, g, j ; None : e, h,
16. achiral : I, III; chiral : II, IV, V, VI

Et

H H
H
17. (a) H (b)
H
H H
H H
H

18. (a) cis (b) cis (c) cis (d) trans (e) trans (f) trans
19. D

Me Me Me Me

H OH HO H H OH HO H

20. Total 4 H H Me Me

Me Me H H
D-Trans L-Trans D-cis L-cis

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ISOMERISM CHEMISTRY

Cl
Cl Cl
21.

Cl Cl
Cl
22. 4 23. 9 24. 5 25. 1 26. 1 27. 2 28. 2 29. 2

30. (a) 4 (b) 3 31. (a) 16 (b) 4 32. (a) 4 (b) 4 (c) 2 (d) 8 (e) 4 (f) 4 (g) 4
33. (a) 4 (b) 8 34. 3 35. 2

36. chiral a, b ; meso c 37. 5 38. (a) 0 (b) 1 (c) 2

39. (a) 2 (b) 4 (c) 2 40. (a) enantiomer (b) enantiomer (c) diastereomers

41. (a) 3 & 4 (b) 1 & 3, 1 & 4 (c) 2 (d) 1 & 2, 2 & 3, 2 & 4

42. (a) 2R 3R, 2R 3S, 2S 3S (b) 1 & 3 (c) 2 (d) 1 & 2 ; 2 & 3

43. (i) 3 (ii) 3 (iii) 5 44. (i) 5 (ii) 4

45. (i) 5 (ii) 3

EXERCISE-IV PREVIOUS YEAR QUESTIONS LEVEL-I (JEE MAIN)

1. C 2. B 3. D 4. A 5. A 6. D 7. A
8. B 9. A 10. B 11. A 12. A 13. A 14. C
15. C 16. C 17. A

LEVEL-II (JEE ADVANCED)

1. D 2. D 3. C

1
4. (i) D (ii) Anti form when Y = CH3 & Gauche when Y = -OH
0.18
5. C 6. C 7. AD 8. BCD 9. AD 10. 7 11. 5

12. BD 13. BC 14. B 15. A 16. BC 17. ABC

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