[figure: benzene + succinic anhydride (cyclic five-membered anhydride) $\xrightarrow{\mathrm{AlCl_3}}$ A $\xrightarrow[\mathrm{HCl}]{\mathrm{Zn-Hg}}$ B $\xrightarrow{\mathrm{Conc.\ H_2SO_4}}$ C] What is the structure of C ?

Option 1: [figure: 1-tetralone, 3,4-dihydronaphthalen-1(2H)-one (benzo-fused cyclohexanone with C=O adjacent to the ring fusion)]

[figure: 1-tetralone, 3,4-dihydronaphthalen-1(2H)-one (benzo-fused cyclohexanone with C=O adjacent to the ring fusion)]

[figure: 2-tetralone, 3,4-dihydronaphthalen-2(1H)-one (C=O at the 2-position of the saturated ring)]

[figure: 4-oxo-4-phenylbutanoic acid, $\mathrm{C_6H_5COCH_2CH_2COOH}$]

[figure: 4-phenylbutanoic acid, $\mathrm{C_6H_5CH_2CH_2CH_2COOH}$]

JEE Main 2024 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 9 April 2024, Shift 1, Chemistry Q72

Question 72 of 90 in this shift, Chemistry question 12 of 30, Section A.

[figure: benzene + succinic anhydride (cyclic five-membered anhydride)

\xrightarrow{\mathrm{AlCl_3}}

\xrightarrow[\mathrm{HCl}]{\mathrm{Zn-Hg}}

\xrightarrow{\mathrm{Conc.\ H_2SO_4}}

C] What is the structure of C ?

The figure, in words

Reaction scheme: benzene + succinic anhydride (AlCl3) gives A; Zn-Hg/HCl gives B; conc. H2SO4 gives C. Options are structures: 1-tetralone, 2-tetralone, 4-oxo-4-phenylbutanoic acid, 4-phenylbutanoic acid.

(1)[figure: 1-tetralone, 3,4-dihydronaphthalen-1(2H)-one (benzo-fused cyclohexanone with C=O adjacent to the ring fusion)]Official answer
(2)[figure: 2-tetralone, 3,4-dihydronaphthalen-2(1H)-one (C=O at the 2-position of the saturated ring)]
(3)[figure: 4-oxo-4-phenylbutanoic acid, $\mathrm{C_6H_5COCH_2CH_2COOH}$ ]
(4)[figure: 4-phenylbutanoic acid, $\mathrm{C_6H_5CH_2CH_2CH_2COOH}$ ]

Official answer

Option 1

NTA final key.

Chapter: Aldehydes, Ketones and Carboxylic Acids
Topic: Aromatic Hydrocarbons
Idea tested: Intramolecular Friedel-Crafts

Same topic in other shifts

All Aromatic Hydrocarbons questions

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.