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    I'm slightly confused on what the actual equation is (I'm pretty sure I've confused myself here but anyway).
    In my book it's:
    C6H5NH2 + HNO2 +2HCl --> C6H5N2+Cl- + 2H20

    (or phenylamine + nitrous acid + hydrochloric acid --> benzenediazonium chloride + water)

    But I've looked online, and in replacement of the nitrous acid, I've seen sodium nitrate, NaNO2. :confused:
    I was just wondering whether this was interchangeable, because of the need to generate the nitrous acid before it reacts with the phenylamine, or whether my book's got a typo?
    Thanks!
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    The two are interchangeable, as both HNO2 and NaNO2 will form the ion NO+ which is needed for the formation of the diazonium
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    (Original post by daydreamaway)
    I'm slightly confused on what the actual equation is (I'm pretty sure I've confused myself here but anyway).
    In my book it's:
    C6H5NH2 + HNO2 +2HCl --> C6H5N2+Cl- + 2H20

    (or phenylamine + nitrous acid + hydrochloric acid --> benzenediazonium chloride + water)

    But I've looked online, and in replacement of the nitrous acid, I've seen sodium nitrate, NaNO2. :confused:
    I was just wondering whether this was interchangeable, because of the need to generate the nitrous acid before it reacts with the phenylamine, or whether my book's got a typo?
    Thanks!
    In fact nitrous acid is never used as it is far too unstable. Instead it is generated 'in-situ' by the reaction between HCl and NaNO2

    HCl + NaNO2 --> HNO2 + NaCl
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    (Original post by daydreamaway)
    I'm slightly confused on what the actual equation is (I'm pretty sure I've confused myself here but anyway).
    In my book it's:
    C6H5NH2 + HNO2 +2HCl --> C6H5N2+Cl- + 2H20

    (or phenylamine + nitrous acid + hydrochloric acid --> benzenediazonium chloride + water)

    But I've looked online, and in replacement of the nitrous acid, I've seen sodium nitrate, NaNO2. :confused:
    I was just wondering whether this was interchangeable, because of the need to generate the nitrous acid before it reacts with the phenylamine, or whether my book's got a typo?
    Thanks!
    to make HNO2 you do this

    NaN02 + HCl = HN02 + NACl


    you can either make the nitrous acid in a seperate stage or combine it in the other formula.
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    (Original post by charco)
    In fact nitrous acid is never used as it is far too unstable. Instead it is generated 'in-situ' by the reaction between HCl and NaNO2

    HCl + NaNO2 --> HNO2 + NaCl
    This is what I've been taught too; it seems that putting HNO2 as a reagent or condition or whatever (question dependent, either in the equation or on the arrow) is wrong for the reason emboldened here. Stick to charco's advice and you should secure all the marks.
 
 
 
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