JEE Advanced 2024 Paper 1 Q06 Chemistry Organic Reactions & Mechanisms Phenol & Haloform / Cumene Process Hard

JEE Advanced 2024 Paper 1 · Q06 · Phenol & Haloform / Cumene Process

Reaction of iso-propylbenzene with $O_2$ followed by the treatment with $H_3O^+$ forms phenol and a by-product $\mathbf{P}$. Reaction of $\mathbf{P}$ with 3 equivalents of $Cl_2$ gives compound $\mathbf{Q}$. Treatment of $\mathbf{Q}$ with $Ca(OH)_2$ produces compound $\mathbf{R}$ and calcium salt $\mathbf{S}$. The correct statement(s) regarding $\mathbf{P}$, $\mathbf{Q}$, $\mathbf{R}$ and $\mathbf{S}$ is(are)

  1. A. Reaction of $\mathbf{P}$ with $\mathbf{R}$ in the presence of KOH followed by acidification gives $(CH_3)_2C(OH)(CCl_3)$ [Figure: H3C-C(OH)(CCl3)-CH3 — i.e., 1,1,1-trichloro-2-methylpropan-2-ol].
  2. B. Reaction of $\mathbf{R}$ with $O_2$ in the presence of light gives phosgene gas.
  3. C. $\mathbf{Q}$ reacts with aqueous NaOH to produce $Cl_3CCH_2OH$ and $Cl_3CCOONa$.
  4. D. $\mathbf{S}$ on heating gives $\mathbf{P}$.
JEE Advanced multi-correct — pick every correct option, then check.
Reveal answer + step-by-step solution

Correct answer:A, B, D

Solution

Cumene process: $iso\text{-}propylbenzene + O_2 \to$ cumene hydroperoxide $\xrightarrow{H_3O^+}$ phenol + acetone. Hence $\mathbf{P} = (CH_3)_2C{=}O$ (acetone). $\mathbf{P} + 3Cl_2 \to CCl_3{-}CO{-}CH_3$ (1,1,1-trichloropropan-2-one) = $\mathbf{Q}$. $\mathbf{Q} + Ca(OH)_2 \to CHCl_3$ ($\mathbf{R}$, chloroform) + $(CH_3COO)_2Ca$ ($\mathbf{S}$). (A) Acetone + chloroform / KOH (haloform-like aldol) gives chloretone $(CH_3)_2C(OH)CCl_3$ — TRUE. (B) $CHCl_3 + \tfrac{1}{2}O_2 \xrightarrow{h\nu} COCl_2 + HCl$ — phosgene formed — TRUE. (C) $\mathbf{Q}$ ($CCl_3COCH_3$) + NaOH gives $CHCl_3 + CH_3COONa$, NOT $Cl_3CCH_2OH$ and $Cl_3CCOONa$ — FALSE. (D) Calcium acetate $(CH_3COO)_2Ca \xrightarrow{\Delta} (CH_3)_2C{=}O + CaCO_3$ — gives acetone $\mathbf{P}$ — TRUE.

Want to drill deeper? Open this question inside SolveKar AI and tap "Why?" on any step — the AI Mentor reads your full solution context and explains until it clicks. Download SolveKar AI →