IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry - can anyone give a detail solution to this organic question

rakesh61

Which of the following is the most basic?

(1)		(2)
(3)		(4)

magiclko

the most basic compound is that one, whose lone-pair are least stabilised....
now we NO2 decreases the electron-density at its ortho and para position... thus stabilising the lone-pairs at the nitrogen of NH2, that means, 1 and 3 are less basic than other two.. now the rest two both have OR- grp at ortho to NH2..., so OR- will increase electron-density at its ortho position, also for the CH3 grps, in the 2nd one , both are attached at ortho to NH2 , so they will increases electron-density at NH2...
thus we see, the lone-pairs at NH2, is least stable in 2nd one (due to high-electron density), so its the most basic

atharvapathak

Second one.

rebel

~~~~~~~~~~~2 nd one is the most basic~~~~~~~~~~~~~~~~~~~~~

10904him

I think the third one is the most basic

sai_nikhithdeshineni

cant we decide by +I or -I effects

magiclko

mesomeric effects always dominate over inductive effects

aditya_arora04

Hi manasi,

Please tell me why is it not 4) . Ethers are electron-donating groups. 4th one is most electron releasing.

Also, please elaborate on mesomeric effect

Are you in XII or XII pass ?

chem4884

consider +M and -M effect

also steric hindrence........so 4 is most basic ...2 will have high steric hindrence

madhusudan.chavan

7819

Basicity of aniline derivatives depends on following factors :

1.Electron donating substituents (EDG) tend to increase and electron withdrawing substituents (EWG) tend to decrease the basicity.

2.The base weakening effect of the EWG and base strengthening effect of EDG is more marked at para position than at meta position (refer the resonating structures).

3.o-substituted anilines are usually weaker bases than aniline regardless of the nature (EDG or EWG) of the substituent. This effect is called the ortho effect and is probably due to combination of steric and electronic factors.

In the light of above rules compounds I & III will be definitely less basic due to NO₂ group. Compound II will be less basic than IV due to ortho effect. Thus compound IV should be most basic.

khinart

2nd one obviously dumbo.

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