Ethylbenzene is generally prepared by acetylation of benzene followed by reduction and not by the direct alkylation of benzene. Think of a possible reason.

Explanation

The direct alkylation of banzene with n-propylchloride by Friedel-Crafts reaction gives isopropylbenzene and not n-propybenzene as the primary carbocation `(CH_(3)CH_(2)overset(+)CH_(2))` rearranges to a more stable secondary carbocation `(CH_(3)overset(+)CHCH_(3))`.
`CH_(3)CH_(2)CH_(2)CI+AICI_(3)toCH_(3)CH_(2)overset(+)CH_(2)+AIbarCI_(4)`
`CH_(3)CH_(2)overset(+)CH_(2)toCH_(3)overset(+)CHCH_(3)`
`C_(6)H_(6)+CH_(6)overset(+)CHCH_(3)tounderset("Isoproptylbenzene")(C_(6)H_(5)CH(CH_(3))_(2))`
Acylation gives keto compound which on reduction forms alkylbenzene.