Question

Aryl halides are less reactive towards nucleophilic substitution reaction as compared to alkyl halides due to:
A.the formation of less stable carbonium ion
B.resonance stabilization
C.longer carbon-halogen bond
D.the inductive effect
E.$sp^2$ - hybridized carbon attached to the halogen

Answer 1

Hint: We know that the aryl halides are more stable than the alkyl halide and the reason for this is that aryl halide has a resonating structure. An alkyl halide does not show resonance hence less sable.

Complete answer:
Let us see the structure of aryl halide:

Now let us see the structure alkyl halide:

Now, let us see why aryl halide is less reactive than alkyl halide towards nucleophilic substitution:
We know that the hybridization of carbon in alkyl halide is \[s{p^3}\] .
Now, \[s{p^3}\] hybridization means the bond between carbon and halogen is less electronegative.
As the bond is less electronegative it will require less energy to break the bond and the reaction can proceed easily.
We also know that the hybridization of carbon in aryl halide is \[s{p^2}\] .
Now, \[s{p^2}\] hybridization means the bond between carbon and halogen is more electronegative.
As the bond is more electronegative it will require high energy to break the bond.
We also know that the lower the polarity of the bond lower is the reaction toward the nucleophile.
And the polarity between the carbon and halogen in alkyl halide is higher than the polarity between the carbon and halogen in aryl halide.
So, alkyl halide is more reactive than aryl halide towards nucleophilic substitution.

Therefore, we can conclude that the correct answer to the question option B and option E.

Note: We know that the aryl compound contains an aromatic ring and hence it has the resonance stabilization energy associated with it while the alkyl contains the open-chain compounds so resonance role will not be possible in alkyl halide.