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Homework Help: [Chemistry] questions on solubilty of bases and naphthalen-2-ol

  1. Nov 30, 2008 #1
    1. The problem statement, all variables and given/known data
    2-hydroxybenzenediazonium ion is allowed to react with naphthalen-2-ol to form 1-(4-hydroxyphenylazo)-2-naphthol

    2. Relevant equations
    1.Why is amine having a different solubility in water and dilute hydrochloric acid?

    2.Why is naphthalen-2-ol dissolves in sodium hydroxide instead of water or acidic aqueous solvent?

    3.Does naphthalen-2-ol react with aliphatics amines and how to use it to distinguish between aliphatics and aromatic amines?

    3. The attempt at a solution
    1.I guess it is because when it dissolve in dilute hydrochloric acid, the H+ ions react with the OH- ions from the amine, so the equilibrium shift towards the right, and therefore amine dissolves better in dilute hydrochloric acid?

    2.Is it related to basify...but I even don't know what is basify. Or it is because naphthalen-2-ol is too bulky to dissolve in water?

    3.My guess is no. But I also don't know why.....

    Really thanks a lot for you guys help
    Last edited: Nov 30, 2008
  2. jcsd
  3. Dec 1, 2008 #2


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    Science Advisor
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    Gold Member

    1. What happens to an amine in acidic solution? It has nothing to do with the alcohol (-OH) functionality...

    2. Think of naphthalene-2-ol as an enol. What would a base do in that case?

    3. To answer this question you need to understand the mechanism of the reaction. Remember that the diazonium salt is added slowly to a solution that contains an excess of NaOH, so the reaction occurs under basic conditions. Diazonium ion is an electrophile in this reaction.
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