Benzyl Chloride is more reactive than Ethyl Chloride both in Sn1 and S

1.	Benzyl Chloride is more reactive than Ethyl Chloride both in Sn1 and Sn2 conditions. -Explain.
Answer» 1-chloro-2-phenylethane is Ph-CH2-CH2-Cl, and if it undergoes the SN1 reaction, the intermediate would be Ph-CH2-CH2(+). Because of the intervening CH2 group, the carbocation that would be formed is an ordinary primary carbocation. So the SN1 reaction will not occur in 1-chloro-2-phenylethane, except perhaps under forcing (HIGH TEMPERATURE) conditions and even then, the carbocation is likely to undergo rearrangement.Benzyl chloride, Ph-CH2-Cl, FORMS the intermediate Ph-CH2(+), and here the carbocation is stabilized by resonance with the benzene ring. [Exercise: draw the four resonance structures of Ph-CH2(+).] This makes benzyl chloride the more REACTIVE towards SN1 reactions.

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