Destroyer IR question

[NDPitch]

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I thought internal alkynes had NO PEAKS, so wouldn't that make it the weakest signal? See attached image. They say the answer is A because it doesn't have a dipole. 😕

 

[spikers220]

Internal alkynes give sharp peaks if they are not symmetrical. Answer A is correct because it does indeed lack a dipole.

 

[Tunaman]

I thought internal alkynes had NO PEAKS, so wouldn't that make it the weakest signal? See attached image. They say the answer is A because it doesn't have a dipole. 😕

You will likely only have to identify major functional groups on the actual exam using IR, I recommend knowing NMR as well

 

[deidel]

why does the cis have a dipole but the trans doesnt? isn't the cis symmetric too??

 

[Troyvdg]

why does the cis have a dipole but the trans doesnt? isn't the cis symmetric too??

alkyl groups are electron donating through induction toward the double bond. If you draw out the vectors, they cancel out for trans, but their additive for cis👍

 

[torobcheh21]

so a molecule without a dipole will have a weaker IR frequency than one with a dipole? is this a general rule?

 

[Troyvdg]

so a molecule without a dipole will have a weaker IR frequency than one with a dipole? is this a general rule?

a molecule without a dipole won't show up with IR at all

 

[torobcheh21]

so is that why A has the weakest signal? cuz it doesn't even show up?

 

[hasanein4u]

alkyl groups are electron donating through induction toward the double bond. If you draw out the vectors, they cancel out for trans, but their additive for cis👍

👍👍