The reactant shown is hydrogenated completely (every C=C, the C=O and the benzene ring) with excess H2 over Ni at high pressure and temperature. Give the degree of unsaturation of the final organic product as an integer.

JEE Advanced levelNumerical answerDifficulty 3 of 3si231

The reactant shown is hydrogenated completely (every C=C, the C=O and the benzene ring) with excess $H X_{2}$ over Ni at high pressure and temperature. Give the degree of unsaturation of the final organic product as an integer.

Numerical answer type, tolerance 0.5.

The reactant shown is 4-vinylbenzaldehyde,

C X_{9} H X_{8} O

, DBE 6. Complete hydrogenation converts the ring to cyclohexane, the vinyl to ethyl and the CHO to

CH X_{2} OH

, giving

C X_{9} H X_{18} O

(4-ethylcyclohexylmethanol). DBE

= (20 - 18) /2 = 1

, the surviving ring.