Explaingenerally haloalkenes undergo nucleophilic substitution reaction whereas haloarens undergo electrophillic substitution reaction

The halogen atom in haloalkanes is more electronegative than the carbon atom attached to it. As a result, carbon atom acquires a partial +ve change and the halogen atom a partial -ve charge.The presence of +ve charge on the carbon atom makes it facilitated to the attacked by nucleiophilic reagent.

On the other hand,due to resonance effect,differences in hybridization of c-atom in c-x bond of haloarene(sp2) , less polarity of c-x bond, halogens are less reactive towards nucleophilic substitution reaction . Due to resonance the election density increases at ortho and para position of haloarenes and thus undergo electrophilic substitution reaction.