Test: Electrophilic Substitution Reactions

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This mock test of Test: Electrophilic Substitution Reactions for Class 11 helps you for every Class 11 entrance exam. This contains 10 Multiple Choice Questions for Class 11 Test: Electrophilic Substitution Reactions (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Electrophilic Substitution Reactions quiz give you a good mix of easy questions and tough questions. Class 11 students definitely take this Test: Electrophilic Substitution Reactions exercise for a better result in the exam. You can find other Test: Electrophilic Substitution Reactions extra questions, long questions & short questions for Class 11 on EduRev as well by searching above.

QUESTION: 1

During nitration of benzene, the active nitrating agent is:

A.
NO₃^–
B.
HNO₃
C.
NO₂⁺
D.
NO₂^–

Solution:

QUESTION: 2

The halogen which is most reactive in the halogenation of alkanes under sunlight is:

A.
Iodine
B.
Chlorine
C.
Fluorine
D.
Bromine

Solution:

The correct answer is Option B.
Fluorination (155 kJ/mol) seems to have relatively high activation energy. The initial reaction (chain initiation) - that is, the homolytic cleavage of a halogen molecule - must, however, occur only a few times.
The subsequent reactions (chain propagation) between a halogen radical and methane, and then between a methyl radical and a halogen molecule, yield another halogen radical.
Therefore, one start reaction may initiate thousands of fluorination reactions. In addition, fluorination is very exothermic, the reaction enthalpy is −431 kJ/mol. As a result, the reaction itself provides enough energy for additional initiation reactions.
Hence, the halogenation of alkanes is violent and very fast in Fluorine.
So the correct option is B.

QUESTION: 3

Identify the correct order of reactivity in electrophilic substitution reactions of the following compounds Benzene, methyl benzene, Chlorobenzene, nitro benzene:

A.
2>1>3>4
B.
2>1>4>3
C.
4>3>2>1
D.
1>2>3>4

Solution:

The correct answer is option A
Electron donating group (EDG) increases the reactivity of electrophilic substitution reaction and electron withdrawing group (EWG) decreases it.

QUESTION: 4

Necessary condition for halogenation in benzene is:

A.
Presence of halogen carrier
B.
Inert atmosphere of nitrogen
C.
H₂SO₄
D.
Fe catalyst

Solution:

THE HALOGENATION OF BENZENE
This page gives you the facts and a simple, uncluttered mechanism for the electrophilic substitution reaction between benzene and chlorine or bromine in the presence of a catalyst such as aluminium chloride or iron.

QUESTION: 5

The function of anhydrous AlCl₃ in the Friedel-Crafts reaction is to:

A.
Absorb water
B.
To produce nucleophile
C.
To produce electrophile
D.
Absorb HCl

Solution:

The function of AlCl₃ in Friedel-Crafts reaction, is to produce electrophile which later attack on benzene.

QUESTION: 6

The function of AlCl₃ in the Friedel Crafts reaction is:

A.
To produce a nucleophile
B.
To absorb hydrochloric acid
C.
To absorb water
D.
To produce an electrophile

Solution:

The correct answer is option D
The function of AlCl3, in Friedel-Craft reaction, is to produce electrophile, which later adds to the benzene nucleus. This electrophilic aromatic substitution allows the synthesis of monoacetylated products from the reaction between arenes and acyl chlorides or anhydrides. The products are deactivated and do not undergo a second substitution. Normally, a stoichiometric amount of the Lewis acid catalyst is required for both the substrate and the product form complexes.
AlCl3 (and other Lewis acids like it) will coordinate to halogens, and facilitate the breaking of these bonds. In doing so, it increases the electrophilicity of its binding partner, making it much more reactive.

QUESTION: 7

Nitration of benzene by nitric acid and sulphuric acid is:

A.
Electrophilic substitution
B.
Free radical substitution
C.
Electrophilic addition
D.
Nucleophilic substitution

Solution:

QUESTION: 8

The compound which is most reactive towards electrophilic substitution is:

A.
Nitrobenzene
B.
Benzoic acid
C.
Benzene
D.
Toluene

Solution:

The correct answer is Option D.
Due to the +I effect of CH3 in toluene, it is more reactive than benzene. Due to electron withdrawing nature of −COOH group in benzoic acid and −NO2 group in nitrobenzene, both benzoic acid and nitrobenzene are less reactive than benzene.

QUESTION: 9

Friedel Crafts reaction of benzene with ethylene in presence of HCl and anhyd. AlCl₃ gives:

A.
Styrene
B.
Stilbene
C.
Ethylbenzene
D.
1,1-Diphenylethylene

Solution:

The correct answer is Option C.
Benzene can be converted into ethyl benzene as follows.
Step-1:—Conversion of benzene into
Benzene is treated with acetyl chloride in presence of anhydrous AlCl₃ to form acetophenone (phenyl ethanone).This is electrophilic substitution reaction.

Step-2:—Reduction of acetophenone into ethyl benzene.
Acetophenone is treated with hydrazine to form acetophenone hydrazone,which on heating in presence of high boiling solvent like ethylene glycol gives ethyl benzene.This reaction is known as Wolff-Kishner reduction.

QUESTION: 10

The compound that is more reactive towards electrophilic nitration:

A.
Toluene
B.
Benzene
C.
Nitrobenzene
D.
Benzoic Acid

Solution:

From the given example, Toluene is the compound that is more reactive towards electrophilic Nitration. Toluene has a CH3 group on benzene ring and due to plus hyperconjugation it activates the presence of electrons inside the ring. Why nitrobenzene and benzoic acid have - M effect,they will draw electron cloud from the benzene ring and have deactivated the benzene ring from electrophilic Nitration.