(a)Azulene has an appreciabel dipole moment.Write the reasonance structure that explains the dipole moment and its aromaticity. (b)In the cse of halogen-substituted azulenes,a halogen atom onC-6can be displace bynucleophile while one onC-1is unreactive towards nucleophile .Rationalise this differemce in behaviou.

(a)Azulene has an appreciabel dipole moment.Write the reasonance struc

1.	(a)Azulene has an appreciabel dipole moment.Write the reasonance structure that explains the dipole moment and its aromaticity. (b)In the cse of halogen-substituted azulenes,a halogen atom onC-6can be displace bynucleophile while one onC-1is unreactive towards nucleophile .Rationalise this differemce in behaviou.
Answer» Solution : The major CONTRIBUTION to the HYBRID must be one that involves charge separation ,having aromatic five-and seven-membered rings. (b) `ArSN` intermediate reaction is favoured by five-membered ring WOTH cyclopentadienyl anion character(aromatic). In the second case`BAR(e)`discoalisation into the other (seven-membered)ring result in eight`bar(e)`-in that ring ,which DOESNOT stablise it.