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Size:  312.1 KB hi, the question asks for the peaks for malicious acid with D20. For the environment circled in blue, I don't know whether that willl be a HC-O environment or a H-C-C=O environment...

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    (Original post by coconut64)
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Size:  312.1 KB hi, the question asks for the peaks for malicious acid with D20. For the environment circled in blue, I don't know whether that willl be a HC-O environment or a H-C-C=O environment...

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    In nmr, the shielding effects are roughly additive, that is to say the shift of this proton will be shifted up by both the neighbouring groups, so the shift would be higher than for HC-O or HCC=O


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    (Original post by MexicanKeith)
    In nmr, the shielding effects are roughly additive, that is to say the shift of this proton will be shifted up by both the neighbouring groups, so the shift would be higher than for HC-O or HCC=O


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    Hi, how can you deduce this? This is only a-level chemistry, so is this something I should learn by heart? Also by 'shielding effects' , do you mean you will choose the one with a higher chemical shift?

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    (Original post by coconut64)
    Hi, how can you deduce this? This is only a-level chemistry, so is this something I should learn by heart? Also by 'shielding effects' , do you mean you will choose the one with a higher chemical shift?

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    Not really something you can deduce, just take it as fact and use it.

    What I mean by shielding effect is:

    A neighbouring C-O deshields the proton i.e. Increases its chemical shift

    A neighbouring C=O also deshields the proton and hence increases its chemical shift

    The proton in the question has both of these groups next door, so it's shift will be increased by both effects to a value above the shift you would expect for either group on its own.

    The idea of shielding and deshielding is possibly above a level, but all it means is that something decreases (shielded) or increases (deshielded) the chemical shift of the proton you're interested in


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    (Original post by coconut64)
    hi, the question asks for the peaks for malicious acid with D20. For the environment circled in blue, I don't know whether that willl be a HC-O environment or a H-C-C=O environment...

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    Is malicious acid intentionally harmful?
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    (Original post by charco)
    Is malicious acid intentionally harmful?
    Sorry I meant malic acid
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    (Original post by charco)
    Is malicious acid intentionally harmful?
    lmao
 
 
 
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