Why haloalkanes are more reactive than haloarenes towards nuclophilic subsition reaction ?

Explanation

Haloarenes are less reactive than haloalkanes towards nucleophilic substitution reactions. This is due to following reasons : i) Resonance effect : In haloarenes, there is delocalisation of `pi` electron. It forms a number of resonating structures which makes haloarenes more stable and decrease the reactivity, ii) Hybridisation of haloarenes : Haloarenes are sp2 hybridised whereas haloalkanes are `sp^3` hybridised. The `sp^2` hybridised carbon is more electronegative than `sp^3` hybridised carbon. So, it can hold the e pair of bond more tightly than `sp^3` hybridised carbon atom in alkyl halide. So, C-X bond cleavage is difficult in aryl halides.