C6H6 →XC6H5-NO2 ;  ‘ X’ in the reaction is

conc.HNO3+conc.H2SO4 is called nitration mixture;conc.sulphuric acid is responsible for the generation of electrophile nitronium ionNO2+;H-HSO4+HO-NO2→HSO4-+H2O+-NO2; H2O+-NO2→H2O+NO2+; <600c....nitro benzene; >600c...m-dinitro benzene;