Download 1.The Group which shows +M effect is, 2) -NO 3) -OH 4) -CHO

Document related concepts

Strychnine total synthesis wikipedia , lookup

George S. Hammond wikipedia , lookup

Elias James Corey wikipedia , lookup

Physical organic chemistry wikipedia , lookup

Transcript
CHEMISTRY
1.The Group which shows +M effect
is,
1) -CN
2) -NO2
3) -OH
4) -CHO
CHEMISTRY
CN, NO2, CHO are electron with
drawing group, but OH is electron
donating group.
Answer is 3
CHEMISTRY
2. The nucleophilic attack by CN- to the
carbonyl group is an example for
1)+ E effect
2) - E effect
3) + M effect
4) - M effect
CHEMISTRY
-E effect involves complete transfer of pi bond present
in carboxyl group by attacking reagents CN-
SO ,it is 2) –E EFFECT
CHEMISTRY
3.Which of the following has zero dipole
moment,
1.cis-but-2-ene
2. trans-but-2-ene
3. chloroform
4. 2-methylprop-1-ene
CHEMISTRY
Trans-2-butene has symmetric structure
SO the answer is 2) Trans-2-butene
CHEMISTRY
4.The product C in the reaction is :
PCl5
LiAlH4
Alc.KOH
CH3 –COOH 
 A 
 B 
C
1) Acetaldehyde
3) Acetylene
2) Ethylene
4) Acetyl chloride
CHEMISTRY
LiAlH4
CH3COOH + 4[H]
Pcl5
CH3CH2 OH
-H2O
Answer is 2
alc
CH3 – CH2 – Cl
-PoCl3
CH2 = CH2
KOH
CHEMISTRY
5.Reagent used to convert an acid to
alcohol is,
1) Na/C2H5OH
3) Zn in dilute HCl
2) Zn-Hg in conc HCl 4) LiAlH4
CHEMISTRY
Answer is 4
CHEMISTRY
6.In the reaction product C is :
NH3
Heat
NaOBr
CH3 - COOH 
 A 
 B  C
1) acetamide
3) ethanamine
2) methanamine
4) bromoethane
CHEMISTRY
NH3
CH3COOH
Heat
NaoBr
CH3COONH4
CH3CONH2
CH3CH2NH2
Answer is 3
CHEMISTRY
7. The process of seperation of racemic
mixture into (+) and (-) enantiomers is
called,
1.racemisation
2. resolution
3. enantiomerism
4. Walden inversion
CHEMISTRY
2. resolution
CHEMISTRY
8.Which of the following compounds
exhibits stereoisomerism?
1) 2-Methylbutene-1
2) 3-Methylbutyne-1
3) 3-Methylbutanoic acid
4) 2-Methylbutanoic acid
CHEMISTRY
H
CH3
C
C
H3C
CH3
H
H3C – CH2 – C – COOH
CH3
Answer is 4
H
H3C
C
CH3
CH2
COOH
CHEMISTRY
9.An organic molecule necessarily shows
optical activity if it
1) contains asymmetric carbon atoms
2) is non-planar
3) is non-superimposable on its mirror
image
4) is superimposable on its mirror
image
CHEMISTRY
3) is non-superimposable on its mirror
image
CHEMISTRY
10.Among cis-and trans-dichloroethene
1) cis form has more heat of combustion
2) trans form is less stable
3) boiling point of trans form is more
4)melting point of cis form is more
CHEMISTRY
1) cis form has more heat of combustion
CHEMISTRY
11.The amino acid which is not optically
active is,
1) Glycine
2) Alanine
3) Serine
4) Proline
CHEMISTRY
Glycine
H
H2 N
C
COOH
H
Alanine
H3 C
CH
COOH
NH2
Serine
HO
CH2
CH
COOH
NH2
Proline
COOH
N
H
Answer is 1
CHEMISTRY
12.The compound obtained when
acetaldehyde reacts with aqueous
NaOH exhibits :
1) Optical isomerism
2) Geometric isomerism
3) Both optical and geometric isomerism
4) Neither optical nor geometric
isomerism
CHEMISTRY
OH
CH3
CH2
C
H
acetaldol
Answer is 1
CH2
CHO
CHEMISTRY
13.In the sequence of reactions
H 3 O
LiAlH4
CH 3  Br 
 A 
 B 

ether
KCN
the end product (C) is :
1) Acetaldehyde
2) Ethyl alcohol
3) Acetone
4) Methane
CHEMISTRY
KCN
CH3
Br
CH3
H3 O+
CN
CH3
COOH
- H2 O
CH3
Answer is 2
LiAlH4
CH2
OH
CHEMISTRY
14.Which one of the following order is
correct regarding the – I effect of the
substituent's ?
1) NR2 < -OR > -F
2) -NR2 > -OR > -F
3) -NR2 < -OR < -F
4) -NR2 > -OR < -F
CHEMISTRY
As the electro negitivity of the
element increases –I – effect also
increases.Among N, F, and O,
flourine atom has high
electronegitivity.
So answer is 3
CHEMISTRY
15. Which of the following reagents react
with ethylamine to give ethyl alcohol?
1) Br2 / KOH
2) Acidified KMnO4
3) HNO3
4) HNO2
CHEMISTRY
CH3
CH2
NH H + OH NO
Answer is 4
CH3
CH2 OH + N2
CHEMISTRY
16.cis-trans isomers can be
differentiated by:
1)Dipole moment
2)Melting point
3)Boiling point
4)All of these
CHEMISTRY
Isomerism means two organic compounds
having same molecular formula but
different physical and chemical
properties.
4)All of these
CHEMISTRY
17.How many chiral isomers can be
drawn from 2-bromo-3-chlorobutane
1)2
2)3
3)4
4)5
CHEMISTRY
If a molecule contains ‘n’ number of chiral
carbon atoms then it posses 2 n
number of optical isomers.
3) 4
CHEMISTRY
18.Hoffmann’s bromamide reaction
converts
1)Amine to alcohol
2)Cyanide to amide
3)Amide to lower amine
4)Aldehyde to ketone
CHEMISTRY
RCONH2 + Br2 + 4KOH
Answer is 3
R – NH2 + 2KBr + K2CO3 + 2H2O
CHEMISTRY
19.Which is used to increase the number
of carbons in the chain ?
1)Wurtz reaction
2)Frankland reaction
3)Alc. KCN
4)All the these
CHEMISTRY
4)All the these
CHEMISTRY
20.Which is used in the descent of series ?
1)Sodalime decarboxylation
2)Hoffmann bromamide reaction
3)Cannizzaro reaction
4)Both (1) & (2)
CHEMISTRY
4)Both (1) & (2)
CHEMISTRY
21.Sodium propionate on sodalime
decarboxylation gives
1)Methane
2)Ethane
3)Propane
4)Butane
CHEMISTRY
Cao
CH3
CH2
COONa + NaOH
Answer is 2
CH3
CH3 + Na2CO3
CHEMISTRY
22.Ethyl bromide on treatment with
Na/dry ether gives
1)Ethane
2)Butane
3)Propane
4)Ethane
CHEMISTRY
CH3
CH2
Br + 2Na + Br
CH3
Answer is 2
CH2
CH2
CH2
CH3
CH3
CHEMISTRY
23.Which of the following cannot be
prepared by wurtz reaction ?
1)Methane
2)Ethane
3)Hexane
4)Octane
CHEMISTRY
To perform Wurtz reaction two alkyl
halides are required.
1)Methane
CHEMISTRY
24.Which effect is a temporary effect and
operates only in the presence attacking
reagent?
1)Mesomeric effect
2)Inductive effect
3)Hyperconjugative effect
4)Electromeric effect
CHEMISTRY
4)Electromeric effect
CHEMISTRY
25. Ammonia is isoelectronic with
1)Methyl free-radical
2)Methyl carbanion
3)Methyl carbocation
4)All of these
CHEMISTRY
Ammonia is SP 3 hybridised and has
planar structure and it is similar to
carbanion.
2)Methyl carbanion
CHEMISTRY
26.Which statement is correct for
inductive effect?
1)It is a permanent effect
2)It is the property of single bond
3)It causes permanent polarization in the
molecules
4)All of these
CHEMISTRY
4)All of these
CHEMISTRY
27.Which of the following has +R
(resonance ) effect?
1)–CN
2)–CHO
3)-Cl
4)-NO2
CHEMISTRY
To exhibit +R – effect, the atom or group
of atoms should have electron donating
nature. The Cl atom has both electron
donating and withdrawing nature on
benzene ring.
3)-Cl
CHEMISTRY
28.If a compound has n dissimilar dissymmetric
carbon atoms, then the possible number of
optical isomerism is,
1)n/2
2) 2n
3) 2√n
4) √2n
CHEMISTRY
2) 2n
CHEMISTRY
29.Which one of the following acids
would u expect to be the strongest?
1)I –CH2COOH
2)Cl -CH2COOH
3)Br -CH2COOH
4)F-CH2COOH
CHEMISTRY
As the high electronegative atom attached
to –COOH group , O-H bond becomes
weak and donates proton easily and
becomes more acidic in nature.
F- atomis highly electronegative atom.
4)F-CH2COOH
CHEMISTRY
30.Which of the following alkyl groups has
the maximum + I-effect ?
1)CH32)CH3CH23)(CH3)2CH4)(CH3)3CH-
CHEMISTRY
+I effect increases as electron donating
group attached to carbon increases.
4)(CH3)3CH-
CHEMISTRY
31.Which organic species has only one
type of hybridized carbon ?
1)CH2=C=CH2

2)CH3- CH -CH3
3)CH3-CΞCH

4)CH2=CH- C H2
CHEMISTRY

4)CH2=CH- CH2
CHEMISTRY
32.which of the following species is
paramagnetic in nature ?
1) free radical
2) carbocation
3) both of these
4) none of these
CHEMISTRY
To show paramagnetic nature atom or
molecule should posses unpaired
electron. Free radicals are the reaction
intermediate having odd electron.
1) free radical
CHEMISTRY
33. which of the following does not show
electromeric effect ?
1) alkenes
2) ethers
3) aldehydes
4) ketones
CHEMISTRY
To show electromeric effect molecule
should have pi bonds. Ethers not have pi
bond.
2) ethers
CHEMISTRY
34. The ortho and para directing group is
1) –COOH
2) -NO2
3) -OH
4)-CN
CHEMISTRY
Electron donating groups are acts as
ortho and para directing group on
benzene ring.
3) –OH
CHEMISTRY
35.which one of the following series
contains electrophile only ?
1)H2O,SO3 ,H30+
2) NH3,H2O,AlCl3
3) AlCl3,SO3,NO2+
4)H20,Cl+,NH3
CHEMISTRY
Electrophiles are electron deficient
species.
3) AlCl3,SO3,NO2+
CHEMISTRY
36. The activating effect of –OCH3 group
attached to the benzene ring can be
explained in terms of :
1) +R effect
2) –R effect
3) + E effect
4) + I effect
CHEMISTRY
OCH 3 is the electron donating group.
1) +R effect
CHEMISTRY
37. The most stable
carbocation is
a)
b)
c)
d)
CHEMISTRY
37. The most stable
carbocation is
A)
CHEMISTRY
38.Inductive effect involves
1) displacement of sigma electrons
2) delocalization of pi electrons
3) delocalization of sigma electrons
4) displacement of pi electrons
CHEMISTRY
1) displacement of sigma electrons
CHEMISTRY
39.The basicity of aniline is less than that
of cyclohexylamine ,this is due to
1) +R effect of –NH2 group
2) – I effect of –NH2 group
3) –R effect of –NH2 group
4) hyperconjugation effect
CHEMISTRY
NH2
Aniline
Answer is 1
NH2
Cyclohexylamine
CHEMISTRY
40. Mesomeric effect involves
delocalization of
1) protons
2) sigma electrons
3) pi electrons
4) none of these
CHEMISTRY
3) pi electrons
CHEMISTRY
41. which of the following species does
not exert a resonance effect?
1) C6H5OH
2) C6H5Cl
3) C6H5NH
2

4) C6H5N H3
CHEMISTRY

4) C6H5 NH3
CHEMISTRY
42. In electrophillic aromatic substitution reaction ,the
nitro group is meta directing because it
1 ) decreases electron density at ortho and
para position
2) decreases electron density at meta position
3) increases electron density at meta position
4) increases electron density at ortho and para
positions
CHEMISTRY
O-
O
N
O
N
OO
N
OO
N
+
+
+
Answer is 1
O
CHEMISTRY
43. Homolytic fission of C-C bond in
ethane gives an intermediate in which
carbon is
1) Sp 3 – hybridised
2) Sp 2 – hybridised
3) Sp – hybridised
4) Sp 2 d – hybridised
CHEMISTRY
Homolytic fission gives free radicals and
are Sp 2– hybridised
1)Sp 2– hybridised
CHEMISTRY
44.Which of the following has meso isomer
also?
1)2-chlorobutane
2)2,3-dichlorobutane
3)2,3-dichloropentane
4)2-hydroxypentonic acid
CHEMISTRY
H3C
H
H
C
C
Cl
Cl
Answer is 2
CH3
CHEMISTRY
45.A molecule of urea can
show
1)Chain isomerism
2)Position isomerism
3)Geometrical isomerism
4)Tautomerism
CHEMISTRY
4)Tautomerism
O
H2 N
C
OH
NH2
HN
C
NH2
CHEMISTRY
CHEMISTRY