Why is the interhalogen #I-Cl# MORE reactive than #Cl_2# or #I_2# in electrophilic addition reactions?

1 Answer
Jun 23, 2017

Answer:

Presumably because #I-Cl# has a definite dipole moment.......

Explanation:

The electronegativity of iodine is LESS than that of chlorine.......and thus we could represent the molecule as #stackrel(delta+)I-stackrel(delta-)Cl#, i.e. with a permanent dipole. I have no data on the relative activities of #I_2# versus #Cl_2# versus the interhalogen, as an electrophile, but we would predict that the reaction of #I-Cl# with #"propylene"# would give #I-CH_2-CHCl-CH_3# NOT #Cl-CH_2-CHI-CH_3#.

And thus #I-Cl# is more polar than #Cl_2# or #I_2#............and thus expected to be more reactive. Anyway, if your text has data please consult them.