SYNTHETIC
ORGANIC CHEMISTRY
1. The credit for synthesizing first organic
compound in the laboratory went to
a) Berzelius
b) Wohler
c) Kolbe
d) Berthelot
Ans : b) Wohler
[Note : (i) N H 4 C l + K C N O − ∆ → N H 4 C N O − ∆ → N H 2 C O N H 2
−KCl
Ammonium Potassium
Ammonium
Urea
Chloride Cyanate
Cyanate
(ii) Later, Acetic acid is synthesized by Kolbe.
Methane is synthesized by Berthelot.
(iii) Berzellius hypothesis or vital force theory. ]
2.
Methane can be converted to ethane
by the reaction
a) Chlorination followed by the reaction with
alcoholic KOH.
b) Chlorination followed by the reaction with
aqueous KOH.
c) Chlorination followed by the wurtz reaction.
d) Chlorination followed by the decarboxylation
reaction.
Ans : c) Chlorination followed by the wurtz
reaction.
CH 4 Cl
Methane hJ
CH 3 -Cl
Na
dryether
C2H6
Ethane
3.The product ‘D' in the reaction is
C2H6
Cl2
hJ
A AqKOH
a) Ethane
c) Methanol
B (i)K2Cr2O7/H+ C
(ii) NaOH
Sodalime
D
b) Methane
d) Ethanol
Ans : b) Methane
[Note :
C2H6 Cl2 C2H5Cl AqKOH C2H5OH (i) K2Cr2O7/H+ CH3COONa Sodalime CH4
hJ
(ii) NaOH
]
4.
Identify the product P in the reaction
+
CH3OH PI3 M alc KCN N H2O/H O LiAlH4 P
a) Methanol
c) Methanal
b) Ethanol
d) Ethanal
Ans : b) Ethanol
[Note :
CH3OH PI3
CH3I alc KCN CH3CN H2O/H+ CH3COOH LiAlH4 C2H5OH ]
5.
Identify the product D in the reaction
C2H5OH K2Cr2O7/H+ A
a)Ethanal
c) Ethanol
Sodalime B Cl2 C AqKOH
hJJ
D
b) Methanal
d) Methanol
Ans : d) Methanol
[Note :
C2H5OH K2Cr2O7/H+ CH3COOH Sodalime CH4 Cl2 CH3Cl aqKOH CH3OH ]
hJ
CONCEPTS
IN
ORGANIC CHEMISTRY
6.
Inductive effect involves
a) Delocalization of V Electron.
b) Delocalization of S Electron
c) Displacement of V Electrons.
d) Displacement of S Electrons.
Ans : c) Displacement of V Electrons.
7. The order of +I effect shown by
H, CH3, C2H5, & C3H7 is
a) C3H7 > C2H5 > CH3 > H
b) H > CH3 > C2H5 > C3H7
c) H > C2H5 > CH3 > C3H7
d) C3H7 > C2H5 > H > CH3
Ans : a) C3H7 > C2H5 > CH3 > H
8. Which of the following represents the
correct order of the activity in the given
compounds
a) FCH2COOH > CH3COOH > BrCH2COOH >ClCH2COOH
b) BrCH2COOH> ClCH2COOH > FCH2COOH >CH3COOH
c) FCH2COOH > ClCH2COOH > BrCH2COOH >CH3COOH
d) CH3COOH > BrCH2COOH > ClCH2COOH >FCH2COOH
Ans : c) FCH2COOH > ClCH2COOH
> BrCH2COOH > CH3COOH
[Note : Stronger the electronegative atom
stronger is the acidic strength]
9. Which one of the following is
the strongest acid.
a)
b)
c)
d)
2-chloropentanoic acid
3-chloropentanoic acid
5-chloropentanoic acid
4-chloropentanoic acid
Ans : a) 2-chloropentanoic acid
[Note : Acidic Strength decreases as the
distance of the halogen atom from
carboxylic group increases.]
10.Which statement is correct for
Inductive effect
a) It is permanent effect
b) It is the property of single bond
c) It cause permanent polarization in the
molecule
d) All are correct
Ans : d) All are correct
11.Which of the following does not
show Electromeric effect
a)
b)
c)
d)
Alkene
Ethers
Aldehydes
Ketones
Ans : b) Ethers
[Note : Because it does not contain
double bond]
12.When H+ approaches the multiple
bond of alkene shows
a)
b)
c)
d)
+M effect
–M effect
+E- effect
–E effect
Ans : c) +E effect
[Note : transfer of Pi- electron takes place
towards the atom where the
attacking reagent attacks]
13.Which statement is wrong for
Electromeric effect
a) It is temporary effect.
b) It is property of Pi- Bond.
c) It take place in the presence of attacking
reagent.
d) It is a permanent effect.
Ans : d) It is a permanent effect.
14.Which of the following has
+R(resonance) effect.
a) CN
b) CHO
c) NH2
d) NO2
Ans : c) NH2
[Note : +R effect : when the electron
displacement is away from
the group.]
15.
Resonance effect involves
a) Migration of hydrogen atom.
b) Delocalization of V Electrons.
c) Delocalization of S Electrons.
d) All are correct.
Ans : c) Delocalization of S Electrons.
ISOMERISM-2
16. Which of the following pairs represents
stereo-isomerism?
a) Geometrical Isomerism and Linkage Isomerism.
b)Geometrical Isomerism and Optical Isomerism.
c) Structural Isomerism and Geometrical Isomerism.
d)Chain Isomerism and Rotational Isomerism.
Ans : b) Geometrical Isomerism and
Optical Isomerism.
17.-But-2-ene exhibits cis-trans isomerism
due to
a) Rotation around C3—C4 Sigma Bond
b) Restricted rotation around C=C Bond
c) Rotation around C1—C2 bond
d) Rotation around C2—C3 double bond
Ans : b) Restricted rotation around C=C
Bond.
18.The lowest alkene which can
exhibit geometrical isomerism is
a) Ethene
b) Propene
c) 1-butene
d) 2-butene
Ans : d) 2-butene
19.Ordinary light is converted into
plane polarized light by passing
through a
a) Nickel prism
b) Glass Prism
c) Nicol Prism
d) Polarimeter
Ans : c) Nicol Prism
20.
a)
b)
c)
d)
Optical activity is measured by
Polarimeter
Abbe’s refractometer
Spectrograph
Radio carbon dating
Ans : a) Polarimeter
21.An organic molecule necessarily
shows optical activity if it
a) Contains (Chiral / Asymmetric) Carbon
atom
b) Is non-planar.
c) Is non super impossible on its mirror
image.
d) Is super impossible on its mirror image.
Ans: c) Is non super impossible on its
mirror image.
22.An organic molecule definitely shows
optical activity if it
a) Contains asymmetric carbon atoms
b) is non-planar
c) does not contain plane of symmetry
d) is super impossible on its mirror image
Ans : c) does not contain plane of symmetry
[Note : All compounds which do not contain plane of
symmetry have Non-super impossible mirror image.
Hence they are optically active. Presence of chiral carbon
atoms is not the sufficient conditions for a molecule to
show optical activity because more compound contain
chiral carbon atoms, but they are optically inactive.]
23.Optical isomers which are mirror
images of each other are called
a)
b)
c)
d)
Enantiomers
Diastereomers
Tautomer
Meso compounds
Ans : a) Enantiomers
24.The conversion of enantiomer into
racemic mixture is known as
a)
b)
c)
d)
Resolution
Racemisation
Chirality
Inversion
Ans : b) Racemisation
25.The process of separation of racemic
mixture into + and – Enantiomers is
called
a)
b)
c)
d)
Racemisation
Resolution
Boiling Point
Walden inversion
Ans : b) Resolution
26.Which of the following is the chiral
molecule
a) CH3Cl
b) CH2Cl2
c) CHBr3
d) CHClBrI
Ans : d) CHClBrI
[Note : Four different groups are
attached to carbon atom.]
HYDROCARBON-2
27.The hybridisation of carbon atom
in cyclopropane is
a) sp
b) sp2
c) sp3
d) d2sp3
Ans : c) sp3
28.The general formula of
Cycloalkane is
a) CnH2n
b) CnH2n+2
c) CnH2n-2
d) CnH2n-4
Ans : a) CnH2n
29.Most stable cycloalkane
according to Baeyer’s strain theory is
a) Cyclobutane
b) Cyclopentane
c) Cyclohexane
d) Cycloheptane
Ans: b) Cyclopentane
a)
b)
c)
d)
Cyclopropane
Cyclobutane
Cyclopentane
Cyclohexane
Ans : a) Cyclopropane
[Note : Angle strain in Cyclopropane = 240441,
Cyclobutane = +90441, Cyclopentane = +00441
Cyclohexane = -50161
According to Baeyer strain theory more the angle
strain, less is the stability of cycloalkane.]
31.The concept of strainless ring of
cyclohexane & Cycloheptane was put
forward by
a)
b)
c)
d)
Baeyer
Sachse
Kekule
Berzelius
Ans : b) Sachse
32.When cyclohexane is poured in water,
it floats because
a) Cyclohexane is in boat form
b) Cyclohexane is in chair form
c) Cyclohexane is in crown form
d) Cyclohexane is less denser than water.
Ans : d) Cyclohexane is less denser
than water.
33.The Least Energetic conformation of
Cyclohexane is
a)
b)
c)
d)
Chair Conformation
Boat Conformation
E, Z Form
Cis Form
Ans : a) Chair Conformation
34.
a)
b)
c)
d)
Benzene was discovered by
Dalton
Faraday
Kekule
Boyle
Ans : b) Faraday
35.The number of Sigma & Pi-Bonds
in a molecule of Benzene
a) 6V
V and 9S
b) 9V and 3S
c) 12V and 3S
d) 6V and 6S
Ans : c) 12V and 3S
36.The number of S-Electron in
benzene molecule are
a)
b)
c)
d)
4
3
5
6
Ans : d) 6
[ Note : 2pz orbital of carbon is not
involved in hybridization.
Each 2pz orbital contain one
unpaired electron. ? a total of
6 S electron. ]
37. Benzene molecule is
a)
b)
c)
d)
Trigonal
Planar
Tetrahedral
Octahedral
Ans : b) Planar
[Note : All the 6 carbon atom of
benzene are present in one
single plane]
38.The number of di-substituted
product of benzene
a)
b)
c)
d)
Two
Three
Four
Five
Ans : b) Three
[Note : Benzene give ortho,
Para, Meta di-substituted
products]
39.Benzene does not give addition
reaction even though it contain 3
double bonds because
a) Double bond change their position rapidly
b) Resonance lowers the energy of benzene
molecule & leads to greater stabilization.
c) Double bond in benzene are strong
d) None of the above.
Ans : b) Resonance lowers the energy of
benzene molecule & leads to
greater stabilization.
40.The overlapping orbitals in Benzene
is of the type
a) sp—sp
b) p—p
c) sp3—sp3
d) sp2—sp2
Ans : d) sp2—sp2
[ Note : Because the carbon atom in
benzene are sp2 hybridised
overlapping between the
carbon atom is sp2—sp2 ]
41.The electrophile in the nitration
reaction of benzene is
a)
b)
c)
d)
Nitronium ion
Nitrinium Ion
Nitrite ion
Nitrate ion
Ans : a) Nitronium ion . i.e., NO2+
42. During the nitration reaction of
benzene concentrated H2SO4 is used as
a) Solvent
b) Dehydrating agent
c) Sulphonating agent
d) Nitronium ion producer.
Ans : d) Nitronium ion Producer.
+
[ Note : HNO 3 + H 2 SO 4 → NO 2 + H 2 O +
Nitronium Ion
—
HSO4
]
43.In benzene, all the six C—C bond
have the same bond length because of
a)
b)
c)
d)
Resonance
Hybridization
Ans : a) Resonance
Isomerism
Chain Isomerism
[Note : Due to resonance, the carbon-carbon
bond length is between c—c single
bond(0.154nm) and c c double bond
(0.134nm) and it is 0.139nm.This is
due to delocalization of S electrons.]
44.The electrophile in the sulphonation
reaction is
a) SO2
b) SO3
c) SO3H
d) SO3+
[ Note : H2SO4 + H2SO4 →
Ans : b) SO3
-SO3 + H3O + 2HSO4 ]
+
45. The function of anhydrous AlCl3
in Friedal Craft’s reaction is
a) To absorb water
b) To absorb Hcl
c) To produce attacking electrophile.
d) To produce nucleophile.
Ans : c) To produce attacking electrophile.
[Note : (i) Friedel Craft’s alkylation reaction
CH 3 Cl + AlCl 3 → CH 3 + + AlCl 4 —
(ii) Friedel Craft’s Chlorination reaction
Cl 2 + AlCl 3 → Cl + + AlCl 4 — ]
46.Adding Chlorine to benzene in the
present of anhydrous AlCl3 is an example
of
a) Addition reaction
b) Substitution reaction
c) Elimination reaction
d) Polymerisation reaction
Ans : b) Substitution reaction
[Note : Benzene undergo electrophilic
substitution reaction ]
47.In Benzene molecule the carbon
atoms are inclined at an angle of
a) 1200
b) 1800
c) 1090 281
d) 600
Ans : a) 1200
[Note : In benzene C-atom are sp2
hybridised and sp2 hybridised
C-atom have the bond angle 1200.]
48.Regarding benzene molecule, which
of the following statement is wrong.
a) It has six identical carbon atom
b) It is an unsaturated compound .
c) It is an unsaturated compound and
answer tests for unsaturation.
a) C—C bond length is identical.
Ans : c) It is an unsaturated
compound and answer tests
for unsaturation.
49.Which one of the following is formed
when benzene ring is attacked by the
elctrophile.
a) Carbon ion
b) Carbocation
c) Nucleophile
d) Free-radical
Ans : b) Carbocation
[Note : Electrophiles takes up electrons form
the benzene ring to form intermediate
carbocation which are stabilized by
resonance structure.]