QAIPMT-2002-Ch-2770: NEET 2002 Chemistry - Class 12 AIPMT-2002-Ch-2770 Solution: Reactivity order of halides for dehydrohalogenation is

atomic radii order : I > Br > Cl > F F, Cl, Br, I belongs to the same group orderly. Atomic radii go on increasing as the nuclear charge increases from top to bottom in a group. The decreasing order of bond length C � I > C � Br > C � Cl > C � F. The order of bond dissociation energy R � F > R � Cl > R � Br > R � I. During dehydrohalogenation C � I bond breaks more easily than C � F bond.So reactivity order of halides R _ I > R _ B r > R _ C l > R _ F