Home
Class 12
CHEMISTRY
Assertion: Electophilic substitution rea...

Assertion: Electophilic substitution reactions in haloarenes occur slowly and require more drastic conditions as compared to those in benzene.
Reason: Halogens are ortho and para-directors.

A

If both assertion and reason are true and reason Is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assetion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the assertion and reason about electrophilic substitution reactions in haloarenes compared to benzene, let's break it down step by step. ### Step-by-Step Solution: 1. **Understanding Electrophilic Substitution Reactions**: - Electrophilic substitution reactions involve the replacement of a hydrogen atom in an aromatic ring with an electrophile. In this case, we are comparing benzene and haloarenes (like chlorobenzene). 2. **Assertion Analysis**: - The assertion states that electrophilic substitution reactions in haloarenes occur slowly and require more drastic conditions compared to benzene. - This is true because the presence of halogen atoms (like Cl, Br) on the benzene ring introduces electron-withdrawing effects (due to their -I effect), which deactivate the ring towards electrophilic attack. Therefore, stronger conditions (higher temperatures, stronger electrophiles) are needed for the reaction to proceed. 3. **Reason Analysis**: - The reason states that halogens are ortho and para-directors. - While it is true that halogens direct electrophilic substitution to the ortho and para positions due to their +R (resonance) effect, they also exhibit a -I (inductive) effect, which withdraws electrons from the ring. This dual behavior can be confusing. 4. **Conclusion**: - Both the assertion and reason are correct statements. However, the reason does not correctly explain why electrophilic substitution in haloarenes is slower than in benzene. The reason focuses on the directing effects of halogens rather than their electron-withdrawing nature that deactivates the ring. 5. **Final Answer**: - The correct option is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion.
To solve the question regarding the assertion and reason about electrophilic substitution reactions in haloarenes compared to benzene, let's break it down step by step. ### Step-by-Step Solution: 1. **Understanding Electrophilic Substitution Reactions**: - Electrophilic substitution reactions involve the replacement of a hydrogen atom in an aromatic ring with an electrophile. In this case, we are comparing benzene and haloarenes (like chlorobenzene). 2. **Assertion Analysis**: ...
Promotional Banner

Topper's Solved these Questions

  • HALOALKANES AND HALOARENES

    NCERT FINGERTIPS ENGLISH|Exercise Polyhalogen Compounds|6 Videos

  • HALOALKANES AND HALOARENES

    NCERT FINGERTIPS ENGLISH|Exercise NCERT Exemplar|27 Videos

  • HALOALKANES AND HALOARENES

    NCERT FINGERTIPS ENGLISH|Exercise Exemplar problems|24 Videos

  • GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS

    NCERT FINGERTIPS ENGLISH|Exercise Assertion And Reason|15 Videos

  • POLYMERS

    NCERT FINGERTIPS ENGLISH|Exercise NCERT Exemplar|9 Videos

Similar Questions

Explore conceptually related problems

(a) Account for the following : (i) Electrophilic substitution reactions in haloarenes occur slowly. (ii) Haloalkanes, though polar, are insoluble in water. (b) Arrange the following compounds in increasing order of reactivity towards S_(N)2 displacement: 2-Bromo-2-Methylbutane, 1-Bromopentane, 2-Bromopentane

Assertion: In case of aryl halides, halogens are moderately deactivating. Reason: Halogens are ortho, para directing groups.

Assertion: Aryl halides undergo nucleophilic substitution reactions with ease. Reason:The carbon halogen bond in aryl halides has partial double bonds character.

Assertion: In monohaloarenes, further electrophilic substitution occurs at ortho and para position Reason: Halogen atom is a ring deactivator

Assertion: Aryl halides are highly reactive towards nucleophilic substitution reactions. Reason: In case of halorenes, halogen atom is attached to sp hybridised carbon atom.

Give reasons for the following (a) The presence of -NO_2 group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution reactions . (b) p-dichlorobenzene has higher melting point than of ortho or meta isomer . ( c) Thionyl chloride method is preferred for preparing alkyl chloride from alcohols.

Assertion : Reason : Alkyl arly ethers on reaction with halogen acids always from aryl halide due to formation of more stable carbocation.

Assertion: Vinyl halides do not undergo substitution reaction. Reason: Although the cation is stablished by loosely bound pi -electron cloud, it least occurs due to high bond strength.

The general electrophilic substitution reaction (replacement of H. by an electrophilic which is an electron deficient species) in aromatic ring is represented as followed. An electrophilic attacks on ortho and para positions which respect to a stronger +m group are present in benzene ring and the electrophilie attacks at meta position with respect to stronger -m group if two -m groups are present in benzene ring. The product of the following reaction is