Wurtz reaction
Alkyl halides react with sodium in dry ether to give  hydrocarbons
containing double the number of carbon atoms present in the halide This reaction is known as Wurtz reaction 1 Nucleophilic substitution
Aryl halides are extremely less reactive towards nucleophilic
substitution reactions due to the following reasons:
(i) Resonance effect : In haloarenes, the electron pairs on halogen
atom are in conjugation with p-electrons of the ring and the
following resonating structures are possible