[mandy]

Chlorobenzene is nitrated to form 4-chloronitrobenzene. When the 4-chloronitrobenzene is mixed with nitric acid and sulphuric acid, while being heated, what is the expected product?  Why? (hint: think resonance).

Normally, I would think that the resulting structure would be 1-chloro-2,4-dinitrobenzene since that would make the NO₂ groups the furthest from each other and therefore more stable, but I don't know how the heat would affect the reaction or where the resonance comes into play.

[russellm72]

Mandy,

Don't worry about the heat as with one nitro group on the ring it is now quite deactivated and needs an extra kick to put another one in.

As for the product think about ortho, meta and para directing effects and the strength of the director. Nitro is a strong meta director but your best plan is to draw out all the possible resonace hybrids.

Good luck...