The order of the rate of S_N1 reactivity for | vedclass

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Question

(B) The rate of $S_N1$ reaction depends on the stability of the carbocation intermediate formed after the departure of the leaving group.$I$ and $II$

Vedclass · Accepted Answer

$I > II > IV > III$

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(B) The rate of $S_N1$ reaction depends on the stability of the carbocation intermediate formed after the departure of the leaving group.$I$ and $II$ are $p$-methoxybenzyl halides. The $-OCH_3$ group at the para position provides strong $+M$ (mesomeric) effect,which stabilizes the benzylic carbocation significantly.Comparing $I$ ($p$-methoxybenzyl bromide) and $II$ ($p$-methoxybenzyl chloride),the bromide ion $(Br^-)$ is a better leaving group than the chloride ion $(Cl^-)$,so $I$ reacts faster than $II$.$IV$ is benzyl chloride,which forms a stable benzylic carbocation but lacks the additional $+M$ stabilization from the $-OCH_3$ group,so it is less reactive than $I$ and $II$.$III$ is $p$-chloroanisole,where the $Cl$ atom is directly attached to the benzene ring. $S_N1$ reaction at this position would form an unstable aryl cation,making it the least reactive.Thus,the order is $I > II > IV > III$.

The order of the rate of $S_N1$ reactivity for the following compounds is:

Similar Questions

Which of the following compounds cannot undergo dehydrohalogenation?

The increasing order of the reactivity of the following halides for the $S_N1$ reaction is:
$(I)$ $CH_3-CHCl-CH_2-CH_3$
$(II)$ $CH_3-CH_2-CH_2-Cl$
$(III)$ $p-CH_3O-C_6H_4-CH_2Cl$

Identify the compound that undergoes $S_{N}1$ mechanism most rapidly.

The major product formed in the following reaction is
$1,2-dichloro-3-methyl-5-nitrocyclopentane$ $\xrightarrow[{Heat}]{{NaOCH_3(1 \ eq.)}}$ ?

$50\%$ of the reagent is used for dehydrohalogenation of $6.45 \ g$ $CH_3CH_2Cl$. What will be the weight of the main product obtained (in $g$)? [At. mass of $H$,$C$,and $Cl$ are $1$,$12$,and $35.5 \ g \ mol^{-1}$ respectively]

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