CLASS :- 12 MCQ
Topic :- chemical reactivity of halo arene
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
Hello arene are generally prepared by halogenation of arenes , hello arene are less reactive than haloalkanes to word nucleophilic substitution but its activity increases in presence of a certain electron withdrawing group . hello arene also undergoes electrophilic substitution reactions by electrophilic reagent . the halogen atom in haloarene exist resonance effect as well as inductive effect the inductive effect stronger compared to resonance effect this effect govern further substitution reaction in aromatic ring reactivity of hello arene toward electrophilic substitution reaction
1 Assertion: aryl Iodide can be prepared by reaction of C6H6 with iodine in the presence of an oxidizing agent as Nitric acid mercuric oxide or iodic acid
Reason : - Oxidizing agent oxidize as HgO , HNO3 or HIO3 , HI into Iodine
2 Assertion:- The nucleophilic substitution reactions in chlorobenzene difficult compared to Chloroethane
Reason:- chlorine - carbon Bond (C -Cl) in chlorobenzene has a partially double bond nature due to delocalization of Pi electrons (Resonance)
3 Assertion:- Nitration of chlorobenzene lead to to formation of ortho and para nitro chloro Benzene
Reason :- Halogen group is Ortho and para directing group
4 Assertion :- 2 ,4,6- tri nitro chloro - Benzene react with ordinary water at the range of temperature 323 K but chlorobenzene React with sodium hydroxide solution range of temperature 623 K and pressure 300 atmosphere
Reason :- Nitrogen group is electron withdrawing group, decrease the electron density over the Benzene ring in 2 ,4,6- tri nitro chloro Benzene
5 Assertion :- chlorobenzene is less reactive than Benzene towards electrophilic substitution reaction
Reason :- chlorine atom has a exerts negative inductive effect And decrease electron density on Benzene ring