I'll give you a clue. A mixture of concentrated sulphuric and nitric acids generates the positively charged nitronium ion. Think of the negatively charged electron density in the benzene ring. There is an electromagnetic (electrostatic) force of attraction between the two species.
Hi Jenz08- I'm afraid I'm still trying to work out what Mechism is. I've never heard of the word, but a google search throws up several hits relating to medicine and biology- including some very simlar questions to yours on Yahooanswers. Is it a real word and what does it mean?