Reactivity of Molecules Reaction Mechanism Flashcards
1
Q
- Electronegativity is defined as the power of an atom in a
molecule to
a) Repel electrons towards itself
b) Attract electrons towards itself
c) Expand itself
d) All of the mentioned
A
b) Attract electrons towards itself
2
Q
- How does the electronegativiy gets affected with the
negative oxidation state?
a) It decreases
b) It increases
c) It remains constant
d) None of the mentioned
A
a) It decreases
2
Q
- The factors on which electronegativity depends upon
a) Valence state of atom
b) Hybridisation
c) Both valence state and hybridisation
d) None of the mentioned
A
c) Both valence state and hybridisation
2
Q
- The electronegativity of sp2 hybridised atom will be
a) 3.29
b) 2.48
c) 3.69
d) 2.75
A
d) 2.75
2
Q
- Arrange the following groups in the order of decreasing
(+I) effect.
a) C6H5O– > COO– > CR3 > CHR2 > H
b) C6H5O– > H > CR3 > CHR2 > COO–
c) CR3 > C6H5O– > H > COO– > CHR2
d) C6H5O– > COO– > CHR2 > CR3 > H
A
a) C6H5O– > COO– > CR3 > CHR2 > H
2
Q
- Which of the following is a permanent electron
displacement effect?
a) Inductomeric
b) Electromeric
c) Inductive
d) All of the mentioned
A
c) Inductive
3
Q
- Select the correct statement from the following option
a) When multiple bonds are present between two
different atoms, electromeric shift towards the more
electronegative atom takes place
b) When multiple bonds are present between two similar
atoms, the first possibility is symmetric alkenes or alkynes
c) When multiple bonds are present between two similar
atoms, the second possibility is asymmetric alkenes or
alkynes
d) All of the mentioned
A
d) All of the mentioned
4
Q
- Arrange the following groups in the order of decreasing
(-I) effect.
a) CN > F > Br > Cl > COOH > I > H
b) COOH > CN > F > Br > Cl > I > H
c) H > COOH > CN > I > Cl > F > Cl
d) CN > COOH > F > Cl > Br > I > H
A
d) CN > COOH > F > Cl > Br > I > H
4
Q
- Which of the following is an application of inductive
effect?
a) Bond length
b) Dipole moment
c) Strength of carboxylic acids
d) All of the mentioned
A
d) All of the mentioned
5
Q
- Due to presence of C – X polar bond in alkyl halide,
alkyl halides are
a) More reactive than corresponding alkane
b) Less reactive than corresponding alkane
c) Equally reactive as corresponding alkane
d) None of the mentioned
A
a) More reactive than corresponding alkane
5
Q
- Relative basic strength of amines does not depend upon
a) Inductive effect
b) Mesomeric effect
c) Steric effect
d) Stabilisation of cation by hydration
A
b) Mesomeric effect
5
Q
- Which of the following is a temporary effect brought
into play at the requirement of attacking reagent?
a) Inductive effect
b) Mesomeric effect
c) Electromeric effect
d) Inductomeric effect
A
c) Electromeric effect
6
Q
- Select the correct statement from the following option.
a) Conjugate effect is stronger than (-I) effect
b) Conjugate effect is weaker than (-I) effect
c) Conjugate effect is same as (-I) effect
d) None of the mentioned
A
a) Conjugate effect is stronger than (-I) effect
7
Q
- When the complete transfer of π-electrons take place
away from the atom at the requirement of attacking
agent, it is called
a) (-E) effect
b) (+E) effect
c) (-I) effect
d) (+I) effect
A
b) (+E) effect
7
Q
- Which of the following is an example of lewis base?
a) ZnCl2
b) BF3
c) NH3
d) FeCl2
A
c) NH3
7
Q
- The positively charged and electron deficient
compounds which have a tendency to form a bond by
accepting the electron pair are known as
a) Electrophiles
b) Nucleophiles
c) Homophiles
A
a) Electrophiles
8
Q
- Which of the following is an incorrect statement about
the nucleophiles?
a) They are electron rich
b) They possess an empty orbital to receive the electron
pair
c) They attack electron deficient centres
d) Examples are: OH–, NH3, H2O etc
A
b) They possess an empty orbital to receive the electron
pair
9
Q
- Lewis acids are the examples of nucleophilic reagents.
a) True
b) False
A
b) False
10
Q
- Which of the following is a resonance effect?
a) Inductive effect
b) Electromeric effect
c) Mesomeric effect
d) Inductomeric effect
A
c) Mesomeric effect
10
Q
- Which of the following molecule will show highest
dipole moment?
a) CH3Cl
b) CH3Br
c) CH3F
d) CH3I
A
c) CH3F
11
Q
- Those groups which are electron repelling and have
lesser electron attracting power than hydrogen show
a) (+E) effect
b) (-E) effect
c) (-I) effect
d) (+I) effect
A
d) (+I) effect
11
Q
- In mesomeric effect, the electrons are transferred from
a) A multiple bonds to an atom
b) A multiple bonds to a single covalent bond
c) An atom with a lone pair to the adjacent single covalent
bond
d) All of the mentioned
A
d) All of the mentioned
12
Q
- The phenomenon in which 2 or more structures,
involving identical position of atoms can be written for a
particular molecule, is called
a) Conjugation
b) Resonance
c) Hyper conjugation
d) Vibration
A
b) Resonance
13
Q
- The resonance energy is defined as a difference in
energy between
a) Two consecutive resonating structures
b) Resonance hybrid and most unstable resonating
structure
c
d) First and last resonating structures
A
a) Resonating structures have a real existence
14
Q
- Select the incorrect option from the following option.
a) Resonating structures have a real existence
b) The actual structure lies between various possible
resonating structures
c) Resonating structures are useful as they allow us to
describe molecules
d) None of the mentioned
A
a) Resonating structures have a real existence
15
Q
- Which of the following is an application of mesomeric
effect?
a) Dipole moment
b) Strength of acids and bases
c) Bond length
d) All of the mentioned
A
d) All of the mentioned
15
Q
- Dipole moment of CH3-CH2-Cl > CH2=CH-Cl.
a) True
b) False
A
a) True
16
Q
- Select the correct statement from the following option.
a) Benzene ring has two different types of bond length for
single and double bonds
b) All the bond length in benzene ring is equal due to
hyperconjugation
c) All the bond length in benzene ring is equal due to
resonance
d) All of the mentioned
A
c) All the bond length in benzene ring is equal due to
resonance
17
Q
- Greater the number of resonating structures for a given
intermediate,
a) Less will be its stability
b) More will be its stability
c) It will not affect its stability
d) None of the mentioned
A
b) More will be its stability
18
Q
- Which of the following is known as Baker-Nathan
effect?
a) Mesomeric effect
b) Inductive effect
c) Hyperconjugation
d) Electromeric effect
A
c) Hyperconjugation
18
Q
- Phenyl group show
a) (+M) effect
b) (+E) effect
c) (+I) effect
d) (-M) effect
A
d) (-M) effect
19
Q
- The resonance energy (kCal/mol) of tertiary butyl is
a) 9
b) 10
c) 11
d) 12
A
d) 12
19
Q
- Hyperconjugation involves the delocalisation of
a) ς bond orbital
b) π bond orbital
c) Both ς and π bond orbital
d) None of the mentioned
A
a) ς bond orbital
20
Q
- Number of hyperconjugation structures in isopropyl
radical is
a) 3
b) 6
c) 9
d) 12
A
b) 6
21
Q
- Larger the number of hyperconjugation structures, the
stability of free radicals will
a) Increase
b) Decrease
c) Remains same
d) None of the mentioned
A
a) Increase
22
Q
- The breaking of a covalent bond in such a way that each
atom separates with one electron of the shared pair is
called
a) Homolytic fission
b) Heterolytic fission
c) Monolytic fission
d) Morpholytic fission
A
a) Homolytic fission
23
Q
- Ethene is devoid of any alpha hydrogen so
hyperconjugation is not possible.
a) True
b) False
A
a) True
24
Q
- Which of the following is a consequence of Baker
Nathan effect?
a) It is helpful in explaining the directive influence of alkyl
groups in aromatic alkyl benzene
b) It is helpful in explaining the relative stability of alkenes
c) It is helpful in explaining the relative stabilities of alkyl
carbocations
d) All of the mentioned
A
d) All of the mentioned
25
Q
- On increasing the number of α-hydrogens, the number
of hyperconjugation structures will
a) Decrease
b) Increase
c) Remains same
d) None of the mentioned
A
b) Increase
26
Q
- When the contributing structure contains the same
number of two-electron bonds as the normal lewis
formula, it will be
a) Heterovalent hyperconjugation
b) Sacrificial hyperconjugation
c) Isovalent hyperconjugation
d) All of the mentioned
A
c) Isovalent hyperconjugation
27
Q
- The compound that can be most readily sulphonated is
a) Benzene
b) Toluene
c) Nitrobenzene
d) Chlorobenzene
A
b) Toluene
28
Q
- The breaking of a covalent bond in such a way that both
the electrons of shared pair are carried away by one of
atom is called
a) Morpholytic fission
b) Monolytic fission
c) Heterolytic fission
d) Homolytic fission
A
c) Heterolytic fission
29
Q
- Select the incorrect statement from the following
option.
a) Fission of covalent bond leads to the generation of
intermediate organic species
b) They are stable and long-lived
c) The presence of reactive intermediates is confirmed by
their detection by spectroscopic methods
d) None of the mentioned
A
b) They are stable and long-lived
30
Q
- A covalent bond between two atoms may be broken in
different ways depending upon
a) Nature of given organic compound
b) Nature of attacking reagent
c) Reaction conditions
d) All of the mentioned
A
d) All of the mentioned
31
Q
- Which of the following is intermediate organic species
based on carbon formed by photolysis?
a) Carbenes
b) Carbo-cations
c) Carbanions
d) Free radicals
A
a) Carbenes
31
Q
- Heterolytic fission takes place between two atoms of
widely different
a) Conductivity
b) Viscosity
c) Electronegtivity
d) All of the mentioned
A
c) Electronegtivity
31
Q
- Select the incorrect statement from the following
option.
a) Heterolytic fission takes place generally in a polar
solvent
b) Heterolytic fission takes place usually at higher
temperatures
c) Cations and anions formed are generally carbon-based
d) None of the mentioned
A
b) Heterolytic fission takes place usually at higher
temperatures
32
Q
- Which of the following is intermediate organic species
based on carbon formed by homolytic fission?
a) Carbenes
b) Carbo-cations
c) Carbanions
d) Free radicals
A
d) Free radicals
33
Q
- Triplet carbene is more stable than singlet carbene.
a) True
b) False
A
a) True
33
Q
- The shape of carbanion is
a) Linear
b) Trigonal planar
c) Pyramidal
d) Bent
A
c) Pyramidal
34
Q
- Stability of free radicals can be explained on the basis of
a) Inductive effect
b) Electromeric effect
c) Hyperconjugation
d) Mesomeric effect
A
c) Hyperconjugation
35
Q
- The formal charge at the carbocation is equal to
a) -1
b) 0
c) +1
d) +2
A
c) +1
36
Q
- The hybridisation of carbocation is
a) Sp
b) Sp2
c) Sp3
d) Sp3d
A
b) Sp2
37
Q
- Arrange the following carbocations in the order of
increasing stability.
a) Benzyl > 30 > 20 > 10
b) Benzyl > 10 > 20 > 30
c) 30 > 20 > 10 > Benzyl
d) 10 > 20 > 30 > Benzyl
A
a) Benzyl > 30 > 20 > 10
38
Q
- Carbonium ions are the intermediates in which the
positive charge is carried by the carbon atom with
___________ electrons in the valence shell.
a) 6
b) 5
c) 4
d) 3
A
a) 6
38
Q
- Positive charge of carbocations can be dispersed by
a) (+I) effect of alkyl group
b) Resonance in allyl or benzyl carbocation
c) Hyperconjugation in 10, 20 and 30 carbocations
d) All of the mentioned
A
d) All of the mentioned
38
Q
- The shape of carbocation is
a) Pyramidal
b) Bent
c) Linear
d) Trigonal planar
A
d) Trigonal planar
39
Q
- The hybridisation of carbanion is
a) Sp
b) Sp2
c) Sp3
d) Sp3d
A
c) Sp3
39
Q
- Alkyl substitution at the carbon bearing positive charge
stabilizes carbocations.
a) True
b) False
A
a) True
40
Q
- Select the correct statement from the following option.
a) Carbanion is the intermediate compound
b) In carbanion, central carbon atom carries negative
charge
c) It possess an unshared pair of electron
d) All of the mentioned
A
d) All of the mentioned
40
Q
- The homolytic bond dissociation energy is inversely
proportional to the
a) Bond length
b) Ease of formation
c) Dipole moment
d) All of the mentioned
A
b) Ease of formation
41
Q
- Which of the following free radical has the maximum
ease of formation?
a) 10
b) 20
c) 30
d) CH3
A
c) 30
42
Q
- Which of the following carbanion is most stable?
a) 10
b) 20
c) 30
d) CH3
A
d) CH3
42
Q
- The structure of carbanion is pyramidal but it undergoes
rapid inversion similar to those of amines.
a) True
b) False
A
a) True
42
Q
- The formal charge at the carbanion is
a) +1
b) -1
c) 0
d) +2
A
b) -1
43
Q
- Which of the following carbanion is least stable?
a) 10
b) 20
c) 30
d) CH3
A
c) 30
43
Q
- The geometry of carbanion is
a) Pyramidal
b) Linear
c) Tetrahedral
d) Trigonal planar
A
a) Pyramidal
44
Q
- Negative charge of carbanion can be dispersed by
a) (+I) effect and resonance
b) (-I) effect and resonance
c) Hyperconjugation
d) (+M) effect and resonance
A
b) (-I) effect and resonance
45
Q
- On increasing the number of alkyl groups, the stability
of carbanions
a) Increases
b) Decreases
c) Remains same
d) None of the mentioned
A
b) Decreases
46
Q
- Due to (+I) effect, the methyl groups are electron
accepting in nature.
a) True
b) False
A
b) False
47
Q
- The atom which defines the structure of a family of
organic compounds and their properties is called
a) Resonating structure
b) Homologous structure
c) Functional group
d) Nucleophile
A
c) Functional group
48
Q
- The functional group in alkyl halide is
a) Hydroxyl group
b) Halogen atom
c) Inert gas
d) All of the mentioned
A
b) Halogen atom
49
Q
- When the nucleophile :OR attacks the RX, the resultant
product will be
a) R – OH
b) ROR
c) R:CN
d) RNHR
A
b) ROR
49
Q
- The halide ion is an extremely
a) Weak base
b) Weak acid
c) Strong base
d) Strong acid
A
a) Weak base
50
Q
- Select the correct statement from the following option.
a) SN2 reaction follows second order kinetics
b) No intermediate is involved in SN2 mechanism
c) SN2 reactions are one-step reaction
d) All of the mentioned
A
d) All of the mentioned
51
Q
- The reactivity order of alkyl halides in SN2 is
a) CH3 X > 10 > 20 > 30
b) CH3 X > 20 > 10 > 30
c) CH3 X > 30 > 10 > 20
d) CH3 X > 30 > 20 > 10
A
a) CH3 X > 10 > 20 > 30
52
Q
- SN1 reaction involves heterolysis to form the
carbocation as an intermediate.
a) True
b) False
A
a) True
53
Q
- Which step in SN1 reaction is a slow rate determining
step?
a) Attack of nucleophile
b) Formation of a racemic mixture
c) Formation of a transition state
d) All of the mentioned
A
c) Formation of a transition state
54
Q
- A low concentration of nucleophile favours the
a) SN2 reaction
b) SN1 reaction
c) Both SN1 and SN1 reaction
d) None of the mentioned
A
b) SN1 reaction
55
Q
- Which of the following reactions are favoured by polar
aprotic solvent?
a) SN1 reactions
b) SN2 reactions
c) Both SN1 and SN1 reactions
d) None of the mentioned
A
b) SN2 reactions
56
Q
- Reaction of alcohol with SOCl2 is
a) SN1
b) SN2
c) SNAr
d) SNi
A
d) SNi
56
Q
- Arrange the following in the decreasing order of
leaving group in nucleophilic substitution reaction.
a) H– > Cl– > HO– > Br– > CH3COO–
b) Cl– > Br– > HO– > H– > CH3COO–
c) Cl– > Br– > CH3COO – > HO– > H–
d) HO– > CH3COO – > H– > Br– > Cl–
A
c) Cl– > Br– > CH3COO – > HO– > H–
57
Q
- The nucleophilic substitutions do not occur in
haloarenes because
a) The carbon-halogen bond is much shorter
b) The carbon-halogen bond is stronger compared to that
in haloalkanes
c) The lone pair of electrons on the halogen participates in
delocalisation with the π-electrons of benzene ring
d) All of the mentioned
A
d) All of the mentioned
57
Q
- Which of the following drastic condition is required for
the substitution in haloarenes?
a) High temperature
b) High pressure
c) Strong concentrated reagent
d) All of the mentioned
A
d) All of the mentioned
58
Q
- The rate of nucleophilic substitution reactions are
higher in the presence of
a) Electron withdrawing groups
b) Electron releasing groups
c) Both electron withdrawing and releasing groups
d) None of the mentioned
A
a) Electron withdrawing groups
58
Q
- Which of the following is rate determining step in
electrophilic substitution reaction?
a) Generation of electrophile
b) Attack by an electrophilic reagent on benzene ring
c) Formation of product
d) All of the mentioned
A
b) Attack by an electrophilic reagent on benzene ring
59
Q
- Which of the following act as a catalysis in the nitration
of benzene?
a) Conc. HCl
b) Dil. HCl
c) Conc. H2SO4
d) Dil. H2SO4
A
c) Conc. H2SO4
60
Q
- Fuming sulphuric acid is the solution of _________%
SO3 in conc. H2SO4.
a) 10
b) 9
c) 8
d) 7
A
d) 7
60
Q
- Which of the following is the necessary condition for
desulphonation?
a) Remove volatile hydrocarbon by steam distillation
b) Low concentration of water
c) High concentration of sulphonating agent
d) A large excess of fuming sulphuric acid
A
a) Remove volatile hydrocarbon by steam distillation
61
Q
- Which of the following act as electrophile in
halogenation?
a) Nitronium ion
b) Sulphonium ion
c) Halonium ion
d) Acylium io
A
c) Halonium ion
61
Q
- Aromatic bromination catalyzed by the Lewis acid
thalium acetate gives
a) Para isomer
b) Ortho isomer
c) Meta isomer
d) Para and ortho isome
A
a) Para isomer
61
Q
- Which of the following is not a product of the reaction
of benzene with CH3Cl and AlCl3?
a) Toulene
b) Isopropyl benzene
c) O-xylene
d) P-xylene
View Answer
A
b) Isopropyl benzene
62
Q
- The reaction in which benzene reacts with alkyl halide in
presence of a lewis acid as a catalyst to produce
alkylbenzene is known as
a) Nitration
b) Halogenation
c) Friedel-Crafts Acylation
d) Friedel-Crafts Alkylation
A
d) Friedel-Crafts Alkylation
63
Q
- How will you convert benzene into n-propyl benzene?
a) Friedel-Crafts Alkylation
b) Friedel-Crafts Acylation
c) Friedel-Crafts Alkylation followed by clemmensen
reduction
d) Friedel-Crafts Acylation followed by clemmensen
reduction
A
d) Friedel-Crafts Acylation followed by clemmensen
reduction
63
Q
- The product of Friedel-Crafts Acylation reactions are
a) Alkylbenzene
b) Alkylamine
c) Arylketone
d) Halobenzene
A
c) Arylketone
64
Q
- An activating substituent group activates
a) Ortho position
b) Para position
c) Both ortho and para positions
d) Meta position
A
b) Para position
65
Q
- Which of the following is meta directing group?
a) –NHCOCH3
b) –COOH
c) –OH
d) –OCH3
A
b) –COOH
65
Q
- Which of the following has the highest activation of
benzene ring?
a) – NHCOCH3
b) –OH
c) –NH2
d) –C6H5
A
c) –NH2
65
Q
- A deactivating substituent group directs
a) Ortho position
b) Para position
c) Both ortho and para positions
d) Meta position
A
d) Meta position
65
Q
- The most stable carbonium ion is
a) Methyl carbonium ion
b) 20 carbonium ion
c) 10 carbonium ion
d) 30 carbonium ion
A
d) 30 carbonium ion
65
Q
- Which of the following is ortho-para directing group?
a) –NHCOCH3
b) –NO2
c) –CN
d) –CHO
A
a) –NHCOCH3
66
Q
- HBr reacts fastest with
a) 2-methylpropan-2-ol
b) Propan-1-ol
c) Propan-2-ol
d) 2-methylpropan-1-ol
A
a) 2-methylpropan-2-ol
67
Q
- HBr reacts fastest with
a) 2-methylpropan-2-ol
b) Propan-1-ol
c) Propan-2-ol
d) 2-methylpropan-1-ol
A
c) Propan-2-ol
68
Q
- In Cannizaro reaction, two molecules of aldehydes are
reacted to produce
a) Alcohol only
b) Carboxylic acid only
c) Alcohol and carboxylic acid
d) Alcohol, carboxylic acid and ketone
A
c) Alcohol and carboxylic acid
