Question

The order of reactivity of haloalkenes is RI>RCl>RBr

Why

Answer 1

On going down the group size of the halides increases and hence stability of the compound decreases as bond length is going to increase resulting in the easy breakdown of the bond and hence reactivity increases.

Also, chlorine-containing haloalkane has high reactivity due to high electronegativity of chlorine.
Thus the correct order of the reactivity is:
R-I >R-Cl> R-Br