CHEM BRAIN

Ethyl Chloride (CH3CH2Cl) > Benzyl Chloride (C6H5CH2Cl) > Chlorobenzene (C6H5Cl)

Ethyl Chloride (CH3CH2Cl): Ethyl chloride is an aliphatic alkyl halide. Aliphatic alkyl halides are generally more reactive in nucleophilic substitution reactions than aromatic alkyl halides. However, ethyl chloride is a primary alkyl halide, so it may be less reactive than some other primary alkyl halides due to steric hindrance.

Benzyl Chloride (C6H5CH2Cl): Benzyl chloride is an aromatic alkyl halide. While aromatic alkyl halides are generally less reactive in nucleophilic substitution reactions compared to aliphatic alkyl halides, benzyl chloride is an exception. Benzyl halides are more reactive than other aromatic halides because the benzyl carbocation intermediate is stabilized by resonance with the aromatic ring. So, benzyl chloride is more reactive than chlorobenzene.

Chlorobenzene (C6H5Cl): Chlorobenzene is also an aromatic alkyl halide. It is less reactive in nucleophilic substitution reactions compared to both ethyl chloride and benzyl chloride due to the electron delocalization in the benzene ring, which stabilizes the molecule and makes the carbon atom less prone to nucleophilic attack