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    (Original post by kawehi)
    I just googled it and apparently it's called the Cannizzaro reaction? There's a mechanism on the wikipedia page
    https://en.wikipedia.org/wiki/Cannizzaro_reaction



    In the original question, the only reactant (besides benzaldehyde) was KOH, so there weren't any other oxidising/reducing agents!
    That's pretty cool actually, not too complicated either haha
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    (Original post by megafidget)
    Definitely wouldn't worry about mechanisms for something like that, it'd probably be something incredibly complex anyway but for those 'suggest' kind of questions I think you're just supposed to apply your knowledge to something you haven't seen/don't explicitly know to answer it without understanding what's going on
    Haha, I know but I like trying to understand it anyway. Also, I generally find it helpful just to try see as much as possible for those suggest questions (I don't know how much it helps but it makes me feel better lol).
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    (Original post by ForeverDay)
    Haha, I know but I like trying to understand it anyway. Also, I generally find it helpful just to try see as much as possible for those suggest questions (I don't know how much it helps but it makes me feel better lol).
    That's probably for the best tbh! At least you'll be less likely to be surprised in the exam and it's a good feeling if you can understand it well
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    (Original post by Serine Soul)
    Just to check, what's the answer?

    And yeah you would
    60 percent

    I will confirm

    thanks.
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    (Original post by Serine Soul)
    Besides some reactions, mass spec and IR, how much of AS are we expected to remember? I'm going to read over my AS notes today
    My teacher advised us to still know all the AS mechanisms for synthesis topics
    Also avogadros constant - i've seen that as an A2 question before
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    guys, the proton on the aldehyde group produces a singlet right?? because its being "shielded" by the O??
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    (Original post by RayMasterio)
    guys, the proton on the aldehyde group produces a singlet right?? because its being "shielded" by the O??
    I don't think that is correct.

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    is the nitration of phenol the same as the nitration of benzene?
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    (Original post by L'Evil Wolf)
    is the nitration of phenol the same as the nitration of benzene?


    From chemguide:
    The -OH group attached to the benzene ring in phenol has the effect of making the ring much more reactive than it would otherwise be.For example, as you will find below, phenol will react with a solution of bromine in water (bromine water) in the cold and in the absence of any catalyst. It also reacts with dilute nitric acid, whereas benzene itself needs a nitrating mixture of concentrated nitric acid and concentrated sulphuric acid.
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    so when is the proton shielded????
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    (Original post by L'Evil Wolf)
    is the nitration of phenol the same as the nitration of benzene?
    i think so, maybe with phenol u dont need to h2so4 as a catalyst since phenol has a higher electron density so could polarise hno3 on its own


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    (Original post by EricPiphany)


    From chemguide:
    (Original post by ranz)
    i think so, maybe with phenol u dont need to h2so4 as a catalyst since phenol has a higher electron density so could polarise hno3 on its own


    Posted from TSR Mobile
    percentage yield was 40 percent from before.

    Thanks for the info guys makes sense. Saw an eight marker from one of the legacy paperpse onn this!
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    Hey guys, hope everyones grinding out revision.

    Could someone please explain this question to me:


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    Attached Images
     
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    Can someone please explain if hydrogen bonds form between C=O groups, or just -OH groups?
    And also, if I have -COOH group, is the proton attached to the oxygen a singlet? Because it's not directly attached to the carbon, so won't be split?
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    guys what do they mean with "in the proton NMR spectrum, the peak at xxx would normally be expected at a chemical shift value about 1ppm to the right"


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    (Original post by zirak46)
    Hey guys, hope everyones grinding out revision.

    Could someone please explain this question to me:


    Posted from TSR Mobile
    is this a legacy paper?


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    (Original post by zirak46)
    Hey guys, hope everyones grinding out revision.

    Could someone please explain this question to me:


    Posted from TSR Mobile
    Legacy paper right? Probably want the answer in terms of of wavelengths and stuff that isn't on the spec anymore.
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    (Original post by zirak46)
    Hey guys, hope everyones grinding out revision.

    Could someone please explain this question to me:


    Posted from TSR Mobile
    Cu+ : 1s2 2s2 2p6 3s2 3p6 3d10 4s0
    Cu2+ : 1s2 2s2 2p6 3s2 3p6 3d9 4s0
    Cu2+ has an incomplete d subshell whereas Cu+ doesn't. The incomplete d subshell is allows transition metal ions to have colour. When a photon of light is absorbed by Cu2+, electrons in the lower energy levels of the 3d subshell jump up to the higher energy levels, and gain energy of a specific wavelength which corresponds to a colour. This colour is absorbed and therefore not seen. The colours that aren't absorbed are seen. The electrons of Cu+ can't jump up that energy level because the 3d subshell is full, there's no space to move up to. Therefore no energy is absorbed, all the colours are reflected and seen as white light.
    You don't need to know that, however, in the question they probably just want you to link the incomplete d subshell to the ability to form coloured complexes.

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    (Original post by mechanism)
    Can someone please explain if hydrogen bonds form between C=O groups, or just -OH groups?
    And also, if I have -COOH group, is the proton attached to the oxygen a singlet? Because it's not directly attached to the carbon, so won't be split?
    If we consider an ester, hydrogen bonds can't form between molecules of the ester because although there is lone pairs on the oxygen atom there is no partially positive hydrogen to be attracted to them. Hydrogen bonds can form between an ester and water, however. Just remember that to have a hydrogen bond, there has to be nitrogen, oxygen, or fluorine in the molecule and a partially positive hydrogen atom. As for the second question, that's right

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    (Original post by ranz)
    guys what do they mean with "in the proton NMR spectrum, the peak at xxx would normally be expected at a chemical shift value about 1ppm to the right"


    Posted from TSR Mobile
    All this means is that you should subtract 1ppm from the chemical shift of the peak at xxx to find its environment on the data sheet.
 
 
 
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