Arenium ion invol

• Aniline reacts with bromine in presence water at room temperature to give a 2,4,6-tribromoaniline, bromination of aniline is an example of electrophillic substitution preferable to the ortho and para position (because these 2 positions of aniline are more electrophilic due to activated benzene ring of amino group) .

• And bromination goes through formation of intermediate arenium (a cyclohadienyl cation ) ions.