The alkene shown is treated successively with (i) HBr (no peroxide), (ii) aqueous KOH, (iii) Cu at 573 K, (iv) I2/NaOH, warm, and (v) dilute HCl. Which structure is the final organic product?

JEE Advanced levelSingle correct optionDifficulty 3 of 3si267

The alkene shown is treated successively with (i) HBr (no peroxide), (ii) aqueous KOH, (iii) Cu at 573 K, (iv) $I X_{2}$ /NaOH, warm, and (v) dilute HCl. Which structure is the final organic product?

The alkene shown is styrene. (i) Markovnikov addition gives (1-bromoethyl)benzene; (ii)

SN X_{1}

substitution gives 1-phenylethanol (D); (iii) dehydrogenation gives acetophenone (B); (iv) the iodoform reaction cleaves

CH X_{3} CO X^{-}

to sodium benzoate and

CHI X_{3}

; (v) acidification gives benzoic acid (A). Phenylacetic acid (C) would need a different carbon chain.