Question

Which of the following carbocations is expected to be most stable?

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

$N{O}_2$ group is a strong electron withdrawing goup. It withdraws electron density toward itself through resonace and $-I$ effect.
Amongst all the canoncal structures given in the options, the structures where $-N{O}_2$ group is directly attached with carbon containg $+$ charge are the least stable.
Since inductive effect minimises as the distance increases, (a) will be the most stable because here $+$ charge is farthest from $-N{O}_2$ group.