The decreasing order of reactivity of meta-ni | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The reaction of aryl halides with $HO^-$ ions follows the Nucleophilic Aromatic Substitution $(S_NAr)$ mechanism. The rate of $S_NAr$ reaction is

Vedclass · Accepted Answer

$II > IV > III > I$

Vedclass · Answer

(B) The reaction of aryl halides with $HO^-$ ions follows the Nucleophilic Aromatic Substitution $(S_NAr)$ mechanism. The rate of $S_NAr$ reaction is directly proportional to the number of electron-withdrawing groups $(-NO_2)$ present on the benzene ring,as they stabilize the Meisenheimer complex intermediate. The number of $-NO_2$ groups in the given compounds are: $(I)$ $meta$-nitro-bromobenzene: $1$ $-NO_2$ group. $(II)$ $2,4,6$-trinitro-bromobenzene: $3$ $-NO_2$ groups. $(III)$ $para$-nitro-bromobenzene: $1$ $-NO_2$ group. $(IV)$ $2,4$-dinitro-bromobenzene: $2$ $-NO_2$ groups. Comparing $(I)$ and $(III)$,the $-NO_2$ group at the $para$ position $(III)$ is more effective at stabilizing the negative charge via resonance than at the $meta$ position $(I)$. Thus,the order of reactivity is $II$ ($3$ $-NO_2$) > $IV$ ($2$ $-NO_2$) > $III$ ($1$ $-NO_2$ at $para$) > $I$ ($1$ $-NO_2$ at $meta$).

The decreasing order of reactivity of $meta$-nitro-bromobenzene $(I)$,$2,4,6$-trinitro-bromobenzene $(II)$,$para$-nitro-bromobenzene $(III)$,and $2,4$-dinitro-bromobenzene $(IV)$ towards $HO^-$ ions is:

Similar Questions

The correct sequence of reagents used in the preparation of $4-$bromo$-2-$nitroethylbenzene from benzene is:

Which of the following has the maximum boiling point?

Give reactions of aryl halides with metals.

What is the decreasing order of reactivity towards nucleophilic substitution for the following compounds?

Amongst the following,the compound that is nitrated with difficulty is

Vedclass Test Series

Exam Paper Generator

Online Exam Module