Question

Why is $ICl$ more reactive than $I_2$ ?

Answer 1

Reactivity comparison of $ICl\&I_2$

$ICl$ is more reactive than $I_2$. This is because interhalogen compounds are more reactive than halogens (except fluorine) as $X-X^{\prime }$ bond in interhalogens is weaker than $X-X$ bond in halogens except $F-F$ bond due to low bond dissociation energy of interhalogen bonds. $I_2$ on the other hand, forms covalent bonds which are stronger and hence difficult to break.