on reaction of toulene with X2 in the presence of FeCl3 in dark , X is attached to ortho position and not at benzylic position .Why?
7Methyl group is ortho and para activating group due to its pushing effect (+I, +R)....so x will be attached at ortho position..moreover X will be able to directly resonate with the benzene ring with its electrons thus increasing the stability.
1but what if we place it in sunlight , then it should be at benzylic position.
1If sunlight is present free radicals are initiated. So it bcoms free radical subs. rx. So it should attack benzylic carbon bcoz of resonance stabilization. But in dark, halonium ion is generated. So it is electrophillic subs rx. Methyl grp is o-,p- directing.
71Not Specifically. All the wavelengths of light carry energy. It is the nature of the electrons that will determine which light wavelength should be absorbed.