3i feel dat I is more stable.
10 Answers
24considerign that in III lone pair of N is used up in double with carbon...
II is most stabe...because octet of N is complete
1one more point. if rearrangement of the carbocation takes place in 2nd structure to the carbon containing -NO2 , then also , it remains allylic carbocation.
1@ aieeee
y u r thinking of rearrangement when u have been asked to compare the stability? :O
ok ..even if u think in that way, the structure u have drawn after rearrangemnt is highly unlikely to be formed as NO2 has strongest(after F-) -I effect. So it will destablise the carbocation(even though in some senses it is allylic, but its certainly nt stable)
think of it like this
N is the secod most electonegative atom,so + charge on it is unstable.
now if u drw the res struct of II and III ,u will find that in III , + chrg will directly come over N
but in II this is not the case,infact in its 2nd res struct, + chrg is also stablised by lone pair of N
24@ yes
we dont need to see all those electronegativity htings right from start...if the ocet rule tells us the stablity level then its fine...no need to solve further