Checkpoints H1 NMR Spectroscopy Q 26 c HELP!

[PB]

ok so I have no idea why Peak B is an octet....there are not even enough Hydrogens in the molecule(7) to split it into eight? How on earth is this possible? Thanks +1

[Alwin]

ok so I have no idea why Peak B is an octet....there are not even enough Hydrogens in the molecule(7) to split it into eight? How on earth is this possible? Thanks +1

(1,1,2-Trichloropropane)

Okay, so firstly, its not technically called an octet, rather a multiplet. What happens is the splitting is 'double spilt'. Sorry if I'm not using the correct terminology but I'm just trying to explain it to you as simply as possible.

So I'm assuming that you got Peak B is the middle (see above picture or the one in checkpoints) carbon, yeah? Now on one neighbouring carbon there are 3H which would give a quartet. BUT on the other carbon there is 1H in a different bonding environment which should give a doublet. What happens is since the hydrogens in the 2 neighbouring carbons are different, they split each other's splitting

The peak B becomes a doublet of quartets (or equally a quartet of doublets). since 2 x 4 = 8, the resultant is a multiplet which appears as an octet.

Hopefully this makes sense to you However, I have never seen a multiplet on a vcaa exam, nor do I believe that its in the study design

[Will Sparks]

(Image removed from quote.)
(1,1,2-Trichloropropane)

Okay, so firstly, its not technically called an octet, rather a multiplet. What happens is the splitting is 'double spilt'. Sorry if I'm not using the correct terminology but I'm just trying to explain it to you as simply as possible.

So I'm assuming that you got Peak B is the middle (see above picture or the one in checkpoints) carbon, yeah? Now on one neighbouring carbon there are 3H which would give a quartet. BUT on the other carbon there is 1H in a different bonding environment which should give a doublet. What happens is since the hydrogens in the 2 neighbouring carbons are different, they split each other's splitting

The peak B becomes a doublet of quartets (or equally a quartet of doublets). since 2 x 4 = 8, the resultant is a multiplet which appears as an octet.

Hopefully this makes sense to you However, I have never seen a multiplet on a vcaa exam, nor do I believe that its in the study design

Correct, multiplets aren't on the exam nor the study design.
Thanks for letting the explanation though!

[PB]

Hopefully this makes sense to you However, I have never seen a multiplet on a vcaa exam, nor do I believe that its in the study design

Hey Alwin,
Cheers for the reply man! I think I sort of get it but if its not on the course than I guess I don't need to fully understand it....it makes me wonder why checkpoints even included it...

[lzxnl]

They USED to be on the course. Then VCAA did their thing and took stuff out. Again.

[Edward21]

They USED to be on the course. Then VCAA did their thing and took stuff out. Again.

Yup, and they removed the addition reactions of non-symmetrical alkenes so in a way it makes it easier, but in another it wasn't even that hard to understand?

[lzxnl]

It IS to a degree; you're forgetting that we're talking VCE here where we just need to remember the results of reactions, not the mechanism. Only through understanding the mechanism can Markovnikov's rule be explained, yet mechanisms are too complex for VCE.

[Edward21]

It IS to a degree; you're forgetting that we're talking VCE here where we just need to remember the results of reactions, not the mechanism. Only through understanding the mechanism can Markovnikov's rule be explained, yet mechanisms are too complex for VCE.

The "rich get richer" rule? We went over that in class where, for example, H-Cl, where the Cl atom is more likely to bond to the C atom with less H atoms on it, wheras the H will more likely bond to the other C with more hydrogen atoms. There was a checkpoints question where our teacher explained this to us in terms of products of a propene addition reaction

[Alwin]

It IS to a degree; you're forgetting that we're talking VCE here where we just need to remember the results of reactions, not the mechanism. Only through understanding the mechanism can Markovnikov's rule be explained, yet mechanisms are too complex for VCE.

Yeah, basically VCE science is pretty bad compared to the rest of the world, especially compared to asian countries

Just a reminder to stay on topic guys