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WorksheetsElectrophilic substitution reactions
Total questions: 20
Worksheet time: 10mins
Which of these is an activating group?
NH2
NO2
COCH3
SO3H
Which is deactivating group?
OH
CHO
CH3
OCH3
Which of the following act as catalysis in the nitration of benzene?
Conc. HCl
Dil. HCl
Conc. H2SO4
Dil. H2SO4
What is electrophilic substitution?
A substitution reaction in which an electrophile is substituted for the electrons in the benzene ring
A substitution reaction in which the benzene ring is attacked by a lone pair of electrons from an electrophile
A substitution reaction in which an electrophile is attacked by the electrons in the benzene ring
Which is least reactive in aromatic electrophilic substitution?
Ethyl Benzene
Anisole
Acetophenone
Chlorobenzene
With respect to the electrophilic aromatic substitution of benzene which of the following is not true?
A non-aromatic intermediate is formed
Benzene acts as an electrophile
A proton is lost in the final step
Resonance forms are important
What will be the attacking electrophile in the reaction of halogenation of Benzene?
Halonium ion
carbocation
Benzene
Halogen
Why does benzene undergo substitution reactions rather than addition reactions
Benzene is a planar, aromatic compound
All the carbon atoms in benzene is sp2 hybridised
All the carbon-carbon bonds in benzene is strong
Benzene has extra stability due to the delocalized π electrons
Aromatic compounds usually undergo which type of reaction
Electrophilic substitution reaction
Electrophilic addition reaction
Nucleophilic substitution reaction
Nucleophilic addition reaction
What is an electrophile?
A species that takes part in a reaction by donating a lone pair of electrons
A species that takes part in a reaction by accepting a lone pair of electrons
A species with a positive charge that takes part in a reaction
What is electrophilic substitution?
A substitution reaction in which an electrophile is substituted for the electrons in the benzene ring
A substitution reaction in which the benzene ring is attacked by a lone pair of electrons from an electrophile
A substitution reaction in which an electrophile is attacked by the electrons in the benzene ring
What are delocalised electrons?
Electrons that are not attached to any of the atoms in a molecule
Electrons that are shared between more than two atoms in a molecule
Electrons that are not attached to any one particular atom but free to move over all the atoms in a molecule
What is a pi bond?
A covalent bond formed by the sideways overlap of p-orbitals
A covalent bond formed by the end-to-end overlap of p-orbitals
A covalent bond formed by the overlap of s-orbitals
What is a nitronium ion?
A negative ion formed by a nitrating mixture of concentrated nitric and sulfuric acids, which acts as an electrophile
A positive ion formed by a nitrating mixture of dilute nitric and sulfuric acids, which acts as an electrophile
A positive ion formed by a nitrating mixture of concentrated nitric and sulfuric acids, which acts as an electrophile
What is acylation?
Substitution of one of the hydrogen atoms of a benzene ring by an acyl group from an acyl chloride
Addition to the benzene ring of an alkyl group from a halogenoalkane
Addition to the benzene ring of an acyl group from an acyl chloride
What is a Friedel-Crafts reaction?
An electrophilic substitution reaction
A reaction to form a C-C bond to an aromatic ring
A reaction involving a Lewis acid
The nitration of benzene uses a nitrating mixture of concentrated nitric acid and concentrated sulfuric acid.
HNO3 + 2H2SO4 → NO2+ + H3O+ + 2HSO4–
Which statement is correct?
HNO3 acts as a base.
HNO3 acts as a catalyst.
HNO3 acts as an electrophile.
HNO3 acts as a reducing agent.
In which one of the reactions is the role of the reagent stated correctly?
A
B
C
D
Which of the following statements regarding electrophilic aromatic substitution is wrong?
Acetyl and cyano substituents are both deactivating and m-directing.
Alkyl groups are activating and o,p-directing.
Ammonium groups are m-directing but amino groups are and o,p-directing.
Chloro and methoxy substituents are both deactivating and o,p-directing.
What is the electrophile in the acylation of benzene?
AlCl3
CO+
Cl+
R-CO+
