Kaplan Ochem Flashcard error?

[Futureortho24]

Hello everyone! Question - in the kaplan flashcards, O34 says T/F the reduction of an alkyne on a metal surface (pd) results in a cis alkene

I thought that was true, but the answer on the flashcard says it is false that it forms an alkane! Am I mistaken or is there an error on the card?

THANKS!!

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[messenger]

it is so an error.

 

[Futureortho24]

WOO HOO! Thanks

 

[asckwan]

Sorry to burst the bubble here, but the flash card is right. Only when paired with a "poison catalyst" (Lindlar's catalyst) or only one equivalent of H2 and Pt will it stop at a cis alkene or else it is potent enough to continue on. Hope that helps out.

 

[Rook]

Sorry to burst the bubble here, but the flash card is right. Only when paired with a "poison catalyst" (Lindlar's catalyst) or only one equivalent of H2 and Pt will it stop at a cis alkene or else it is potent enough to continue on. Hope that helps out.

Not an error
Asckwan is 100% correct

 

[Futureortho24]

I never heard of that - Thanks for the info! It is ok Messenger, I thought there really was an error! I will have to keep this in mind that ONLY when paired with a poison catalyst it reacts in the way I first thought!

Thanks guys!

 

[slayerdeus]

Yea, sometimes you gotta sit back and remember that you are on a forum which anyone can reply to you. The flashcard is indeed correct. When reducing an alkyne using H2/platinum it is syn addition but it doesn't stop at the alkene, it goes all the way through to the alkane.

 

[dat_student]

Hello everyone! Question - in the kaplan flashcards, O34 says T/F the reduction of an alkyne on a metal surface (pd) results in a cis alkene

I thought that was true, but the answer on the flashcard says it is false that it forms an alkane! Am I mistaken or is there an error on the card?

THANKS!!

There is a hidden assumption: you have an excess amnt of H.