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Why is the presence of the nitro group at the meta position to the chlorine group does not increase the reactivity in the replacement of the -Cl group by the -OH group (on treatment with NaOH) ??? The presence of the nitro group at the ortho and the para positions increases the reactivity !!! but the presence of nitro group at the meta position does not increase the reactivity why??? Pls explain

Why is the presence of the nitro group at the meta position to the chlorine group does not increase the reactivity in the replacement of the -Cl group by the -OH group (on treatment with NaOH) ???


The presence of the nitro group at the ortho and the para positions increases the reactivity !!! but the presence of nitro group at the meta position does not increase the reactivity why???


 


Pls explain

Grade:12

2 Answers

vikas askiitian expert
509 Points
11 years ago

this is example of aeromatic neucliophilic substitution reaction ...in these reactions first step is addition of neuliophile & thus negative charged is introduced at adjecent position (ortho) ...

now due to resonance , delocalisation of pi electrons take place & -ve charge is now at para so , if any electron withdrawing group is placed at ortho or para pos then it will disperse the charge & hence stablity is increased on other hand if any EDG is present at ortho or para then it will tend to decrease stablity...

vikas askiitian expert
509 Points
11 years ago

if NO2 is at meta pos then no such stablity of intermediate is observed coz resonance is not possible

in meta position so if NO2 is at ortho-para then rate becomes faster & if NO2 is at meta then rate is slower..

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