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    Organic identification where I have to identify compounds.
    My teacher also said that u.v/visible spectras will be involved, could someone explain as I haven't covered this.
    What relevence will these spectras be to the identification of the compound?

    The exam will be in the format, observations and inferences if that helps.
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    (Original post by Widowmaker)
    Organic identification where I have to identify compounds.
    My teacher also said that u.v/visible spectras will be involved, could someone explain as I haven't covered this.
    What relevence will these spectras be to the identification of the compound?

    The exam will be in the format, observations and inferences if that helps.
    not much to go on!

    UV spectra gives info on conjugation (alternate double and single bonds) and aromatic compounds and using certain rules (Woodward's I think - but could easily be wrong) suggests possible groups either attached to the conjugation or in nearby positions by studying the absorptions in the UV region of the spectrum.

    Visible spectrometry is only useful for coloured compounds such as transition metals (logically) as far as I know.

    Organic analysis nearly always uses the far more useful NMR, IR and MS for structural elucidation
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    I know this is awkward because I have only covered some organic chemistry, but could someone give me some practice questions?

    One question, why does no reaction occur between 2,4dinitrophenylhydraxine and propanoic acid? Why is the C=O in a propanoic acid not a carbonyl group?
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    2,4-DNP is a classic test for the presence of a carbonyl group (aldehydes and ketones - produces an orange ppt), and could also be used to distinguish between aldehydes and ketones.

    Propanoic acid is not a carbonyl compound because the carbon on the C=O is also directly attached to another functional group.
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    To 1 cm3 of distilled water add 10 drops of ethanoic acid and then a squirt of sodium hydrogen carbonate solution

    To 1 cm3 of distilled water add 10 drops of ethanol and then a squirt of sodium hydrogen carbonate solution

    How am I supposed to tell the difference between an alcohol and a carboxylic acid in this test?

    edit: ignore me, it's just neutralisation, doh!
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    (Original post by Widowmaker)
    I know this is awkward because I have only covered some organic chemistry, but could someone give me some practice questions?

    One question, why does no reaction occur between 2,4dinitrophenylhydraxine and propanoic acid? Why is the C=O in a propanoic acid not a carbonyl group?

    which specific area of organic chemistry do you want questions on?
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    (Original post by charco)
    which specific area of organic chemistry do you want questions on?
    tests for functional groups mainly
 
 
 
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