Which sequence gives n-propylbenzene as the major product from benzene?

A $CH X_{3} CH X_{2} CH X_{2} Cl$ / anhydrous $AlCl X_{3}$
Bpropene / $H X_{3} PO X_{4}$
C $CH X_{3} CH X_{2} COCl$ / anhydrous $AlCl X_{3}$ ; then hot alkaline $KMnO X_{4}$
D $CH X_{3} CH X_{2} COCl$ / anhydrous $AlCl X_{3}$ ; then Zn-Hg / conc. $HCl$

Answer: D

Direct alkylation with 1-chloropropane or propene gives isopropylbenzene by carbocation rearrangement. Acylation gives propiophenone (the acylium ion does not rearrange), and Clemmensen reduction converts

C = O

CH X_{2}

, giving

C X_{6} H X_{5} - CH X_{2} CH X_{2} CH X_{3}

. Permanganate would give benzoic acid.

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Which sequence gives n-propylbenzene as the major product from benzene?

Answer: D

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