Identify $A$ in the given chemical reaction. $\mathrm{H}_{2} \mathrm{C}^{/ \mathrm{CH}_{3}}$ $\xrightarrow[\mathrm{CH}_{2}]{\mathrm{HC}}{ }_{\mathrm{CH}_{3}}^{\mathrm{CH}}$ 'A' major product

JEE Main · 2021 · 25 Feb 2021 · Shift 1 · Hydrocarbons

Identify

A

in the given chemical reaction.

H_{2} C^{/ CH_{3}}

HC CH_{2}_{CH_{3}}^{CH}

'A'
major product

(A)(see structure)
✓ Correct
(B)(see structure)
(C)(see structure)
(D)(see structure)

Answer: (A)

Solution

Molybdenum oxide at 773 K and 10-20 atm is the aromatisation (dehydrocyclisation) condition: an alkane of six or more carbons closes to a six-membered ring and is then dehydrogenated to an arene, losing four molecules of hydrogen in all. The alkane here carries seven carbons, so the ring that closes is a six-membered one with the seventh carbon left outside as a methyl group, and dehydrogenation of that ring makes it benzenoid. The major product is toluene.

JEE Main · 2021 · 25 Feb 2021 · Shift 1 · Single correct option

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