What happens when FeF3 is reacted with benzene?
Iron catalyst will not be needed as Fluorine will react directly with benzene explosively,  the probable product formed would be hexaflurocyclohexane , which can predicted by looking at similar reaction of chlorine with benzene in presence of UV rays which is mentioned in NCERT class 11 chemistry  Textbook.

(Replace $Cl$ with $F$  and since fluorine is more reactive UV light is not needed.)