An unsaturated hydrocarbon \(X\) absorbs two hydrogen molecules on catalytic hydrogenation, and also gives following reaction: \(\mathrm{X} \xrightarrow[\mathrm{Zn} / \mathrm{H}_{2} \mathrm{O}]{\mathrm{O}_{3}} \mathrm{~A} \xrightarrow{\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}\right]^{+}} \mathrm{B}\) (3-oxo-hexanedicarboxylic acid) X will be :

JEE Main · 2020 · 08 Jan 2020 · Shift 2 · Hydrocarbons

An unsaturated hydrocarbon

X

absorbs two hydrogen molecules on catalytic hydrogenation, and also gives following reaction:

X O_{3} Zn / H_{2} O A [Ag (NH_{3})_{2}]^{+} B

(3-oxo-hexanedicarboxylic acid)
X will be :

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

Answer: (D)

Solution

On catalytic hydrogenation

X

takes up two molecules of

H X_{2}

, so it holds two degrees of unsaturation. Ozonolysis followed by the oxidative

[Ag (NH X_{3}) X_{2}] X^{+}

work-up, which turns aldehyde fragments into carboxylic acids, gives a single six-carbon product, 3-oxo-hexanedicarboxylic acid,

HOOC - CH X_{2} - CO - CH X_{2} - CH X_{2} - COOH

. A single open-chain product from cleaving two double bonds means the two double bonds lay in a ring, and matching the carbon count and the central ketone points to a seven-membered ring with double bonds at the 1 and 4 positions, that is 1,4-cycloheptadiene.

JEE Main · 2020 · 08 Jan 2020 · Shift 2 · Single correct option

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JEE Main · 2020 · 08 Jan 2020 · Shift 2 · Hydrocarbons

Solution

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