Pent-3-yn-1-ol, CH3-C#C-CH2CH2OH, is treated first with Na in liquid NH3 and the product is then oxidised with PCC in CH2Cl2 (no isomerisation of the double bond occurs). The final product is

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JEE Advanced levelSingle correct optionDifficulty 3 of 3ro125

Pent-3-yn-1-ol, $CH X_{3} - C \equiv C - CH X_{2} CH X_{2} OH$ , is treated first with Na in liquid $NH X_{3}$ and the product is then oxidised with PCC in $CH X_{2} Cl X_{2}$ (no isomerisation of the double bond occurs). The final product is

A(E)-pent-3-enal
Bpentanal
C(E)-pent-2-enal
D(Z)-pent-3-enal

Answer: A

Na/liquid

NH X_{3}

reduces the alkyne by anti addition to the trans alkene, (E)-pent-3-en-1-ol, leaving the alcohol intact. PCC then oxidises the primary alcohol to the aldehyde and stops there. The product is (E)-

CH X_{3} CH = CH - CH X_{2} CHO

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Pent-3-yn-1-ol, CHX3​−C≡C−CHX2​CHX2​OH, is treated first with Na in liquid NHX3​ and the product is then oxidised with PCC in CHX2​ClX2​ (no isomerisation of the double bond occurs). The final product is

Answer: A

More questions on Catalytic hydrogenation and metal hydride reductions (LiAlH4, NaBH4, DIBAL)

Pent-3-yn-1-ol, $CH X_{3} - C \equiv C - CH X_{2} CH X_{2} OH$ , is treated first with Na in liquid $NH X_{3}$ and the product is then oxidised with PCC in $CH X_{2} Cl X_{2}$ (no isomerisation of the double bond occurs). The final product is