Benzene reacts with Chlorine gas in the presence of iron trichloride to yield hexachlorobenzene. However, when it reacts with fluorine gas, it forms a quinoid product (I would actually draw it for them - no need to know the name). Why the difference?
Fluorine is much more reactive than chlorine, even destroying the aromaticity. This is at the expense of the very strong C-F bonds (good orbital size and energy overlap) that are formed. C-Cl bonds are weaker so even when benzene is "burnt" in chlorine, the aromatic ring stays intact.
RB
Related Chemistry A Level answers
All answers ▸At 25 °C, the initial rate of reaction is 3.1 × 10−3 mol dm−3 s−1 when the initial concentration of C is 0.48 mol dm−3 and the initial concentration of D is 0.23 mol dm−3 . Calculate a value for the rate constant at this T when rate = k [C][D].
If you could give your best revision tip for exam preparation what would it be?
How does a acid buffer work?
Explain how the electron pair repulsion theory can be used to deduce the shape of, and the bond angle in, NH3.