I need help with an NMR question!

[airstrikee]

I attached an image for the nmr of 2-pentanone and I do not understand why there is a sextet. On my other attached image, Hc would be split by both Hd and Hb. I don't understand why this would be a sextet if it is being split by two unequivalent hydrogen groups within a 3 sigma bond distance. On the NMR, for Hc why do we not see a triplet of quartets, or a quartet of triplets? I'm probably missing something here. Some help would be very appreciated! Thank you

---

Members don't see this ad.

 

[SpaceBuff12]

The Hc hydrogens have 5 neighboring hydrogens on adjacent carbons. Using the n+1 rule you would expected a signal with six peaks.

Edit: For clarification, the fact that Hb and Hd hydrogen atoms are non-equivalent is irrelevant for the MCAT.

 

[airstrikee]

So when would non-equivalent hydrogens become relvant in terms of complex splitting patterns?

 

[SpaceBuff12]

So when would non-equivalent hydrogens become relvant in terms of complex splitting patterns?

You'll never see complex splitting on the MCAT.

I edited my previous response for clarity.

 

[chemtopper]

The Hc hydrogens have 5 neighboring hydrogens on adjacent carbons. Using the n+1 rule you would expected a signal with six peaks.

Edit: For clarification, the fact that Hb and Hd hydrogen atoms are non-equivalent is irrelevant for the MCAT.

Yes right it is Hc which splits with n+1 rule and MCAT exam will not test you for complex splitting.