Dear Ajay Kanungo

please specify position of both F atom....... i think it is possible with Nitration by Nitrating mixt. at control tepm'....

Most electron density is removed first from the ortho positions by induction, then from the meta positions, and then from the para position.

Any conjugation of the lone pairs on fluorine with the π system would increase the electron density in the ortho and para positions. Both effects favour the para position and this is where most substitution occurs. Fluoro benzne is more reactive than other halogens. so most substitution (Nitartion) where ocuurs in para positions only in the case of mono substituted halogens. you are not mentioned the position of fluorine.

So i think it will not possible in ortho position.

qustion is little complecation, but nitration is simple an electrophylic subsitution reaction. Try this take 1:1 mole of fluoro benzene : Con HNO3 of 50 ml in 100 ml beaker stirr the solution above at room temperature but not exceeding 40 C in presence of sulphuric acid or any lewis acid catalyst for an hour, may you will get p-fluro benzen derivative. If you go to 1:2 thermodynamically more favor to atack on m- position and maintain as mentioned temperature by use of sulphuric acid.