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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ro245

The compound shown contains an alkene and a terminal alkyne. Select ALL correct statements.

  1. A over Lindlar catalyst converts the alkyne into an alkene and leaves the existing alkene unchanged, giving a diene.
  2. BNa in liquid without an added proton source (no ) does not reduce the terminal alkyne because it is deprotonated to the acetylide.
  3. C with excess Pd/C gives hexane.
  4. DNa/ converts the existing C=C into a C-C single bond while leaving the alkyne unchanged.

Answer: A, B, C

The compound is hex-5-en-1-yne. Lindlar catalyst gives hexa-1,5-diene (true); in Na/ without an added proton source a terminal alkyne is deprotonated by the amide formed and the acetylide anion resists further reduction (true); exhaustive hydrogenation gives hexane (true). Isolated alkenes are not reduced by Na/, so statement 4 is false.
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