The term 'aromatic' is derived from Latin word 'aroma' which means sweet or fragrant odour.
Characteristics of aromatic hydrocarbon
i) They are cyclic, planar hydrocarbon having 5,6 or 7 Carbon atoms in a ring
ii) They burn with 'sooty flame'. They contain higher percentage of carbon than in aliphatic hydrocarbon
iii) Although they contain double bond they do not respond addition reaction. Rather, they prefer substitution reaction
iv) They follow Huckel's rule
Huckel's rule:" The cyclic, planar compound having (4n + 2)π delocalized electrons show the properties of aromaticity"
n = 0, 1 , 2 , 3 .......... number of ring