Question

Which one is more reactive from methyl chloride and methyl iodide ?

Answer 1

$C{H}_3-I$ will be more reactive than $C{H}_3-Cl$ because $I^{-}$ ion is a better leaving group than $C{l}^{-}$ ion.

Alternatively, bond dissociation enthalpy of $C-I$ bond is less than that of the $C-Cl$ bond.