help :)

[sam0001]

http://en.wikipedia.org/wiki/Malic_acid

how many peaks would be in the HNMR?

[Hutchoo]

7)'does malic acid have 4 or 5 hydrogen environments? Formally, 5 H environments. But the carboxyl group is very good at de-shielding the acidic H+, and so you'll find the two acidic H+ will most likely overlap. This is due to the finite precision of NMR instruments though. If we were to build the ideal instrument (i.e. instrument with infinite resolution and perfect precision, which is impossible), we will have 5 peaks, but in real instruments we will only see 4.


Thanks a lot