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    Hi for this question, it asks to identify E and F. I understand that E is propan-2-ol and F is a propanone. But there is a small absorption at the 3000cm^-1. I know that F is definitely a ketone but how can you justify the small absorption at 3000-3500cm^-1?

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    My guess is that it's the C-H single bonds.
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    (Original post by Kvothe the Arcane)
    My guess is that it's the C-H single bonds.
    your guess = correct

    w00t
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    (Original post by Pigster)
    your guess = correct

    w00t
    There are two absorptions though, are they both from the C-H bond? Thanks
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    (Original post by coconut64)
    There are two absorptions though, are they both from the C-H bond? Thanks
    There's more than 2. Basically everything in that region is from X-H bonds, and you get a lot of peaks from vibrations associated with C-H bonds in organic molecules. That spectrum is very typical in the region around 3000 wavenumbers.
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    (Original post by alow)
    There's more than 2. Basically everything in that region is from X-H bonds, and you get a lot of peaks from vibrations associated with C-H bonds in organic molecules. That spectrum is very typical in the region around 3000 wavenumbers.
    So carboxylic acid absorption is always much lower and broader and more distinguishable than these kind of absorption ? How do you not mistake this absorpotion with the cooh or O-H absorption?

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    (Original post by coconut64)
    So carboxylic acid absorption is always much lower and broader and more distinguishable than these kind of absorption ? How do you not mistake this absorpotion with the cooh or O-H absorption?

    Thanks
    O-H is good at hydrogen bonding and is a very polar bond, these two factors lead to 2 common features of COOH and OH absorbtion bands:

    1) they are broad- due to hydrogen bonding

    2) they absorb very strongly -because they are polar (you don't need to worry about the reasons behind this
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    (Original post by MexicanKeith)
    O-H is good at hydrogen bonding and is a very polar bond, these two factors lead to 2 common features of COOH and OH absorbtion bands:

    1) they are broad- due to hydrogen bonding

    2) they absorb very strongly -because they are polar (you need to worry about the reasons behind this
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    (Original post by coconut64)
    Thanks
    Sorry, it was meant to say you don't need to worry about the reasons for OH absorbing strongly, ive corrected my previous post now
 
 
 
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