Assertion (A) : Carbon halogen bond in aryl and vinyl halides are unusually shorter.
Reason (R) : Chlorobenzene, and vinyl chlorides undergo $S_N1$ and $S_N2$ reaction in general.
In the light of the above statements, choose the most appropriate answer from the options given below :
Analysis of Statements:
- Assertion (A): The statement claims that the carbon-halogen bond in aryl and vinyl halides is unusually shorter.
- In aryl halides (like chlorobenzene), the C-X bond has partial double bond character due to resonance between the benzene ring and the halogen's lone pairs. This resonance effect shortens the bond compared to a single bond.
- In vinyl halides (like vinyl chloride), the carbon atom attached to the halogen is sp2 hybridized. sp2 hybridized orbitals have more 's' character than sp3 hybridized orbitals (found in alkyl halides). This increased 's' character leads to a shorter and stronger C-X bond.
- Therefore, Assertion (A) is correct.
- Reason (R): The statement claims that chlorobenzene and vinyl chlorides undergo $S_N1$ and $S_2$ reactions in general.
- Aryl halides (like chlorobenzene) are generally unreactive towards nucleophilic substitution reactions ($S_N1$ and $S_N2$). This is because the C-X bond is strong due to partial double bond character, and the formation of an aryl carbocation (needed for $S_N1$) is highly unfavorable.
- Vinyl halides are also resistant to nucleophilic substitution. $S_N2$ reactions are hindered sterically, and $S_N1$ reactions are difficult due to the instability of the vinyl carbocation.
- Therefore, Reason (R) is incorrect.
Conclusion:
Based on the analysis, Assertion (A) is correct, while Reason (R) is incorrect.
The most appropriate answer is that (A) is correct but (R) is not correct.
Important Questions from Mixed Topic (CUET PG)
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- What is the key guide to statecraft in the realist tradition?
- Chronologically arrange the events in the Cold War period.
A. Berlin Wall is constructed
B. Communist China joins the UN
C. Soviet invasion of Czechoslovakia
D. Berlin Blockade
Choose the correct answer from the options given below: Morgenthau's principles of political realism are:
A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
C. International Politics is an arena of conflicting self-interests
D. The ethics of international relations is situational ethics which is very different from private morality
Choose the correct answer from the options given below:Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?
