Ary halides (Ar-X) are unreactive in `SN^2` reaction because they are sttabilised by resonamece
so (C-X) bond has partical double bond character and is a strong bond . Only those (Ar-X) which contian ` EWG` (e. g. -` No_2 ` at o- and p-positions ) undergo `ArSn` reaction, and only aromatic amines containing ` EWG` at o-and p-posotion acan be prepared by Gabrel method
