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Solubility doubt

  1. Sep 9, 2012 #1
    I was solving an exercise where I had to judge (true or false) 5 statements. One of them said:

    "Sodium benzoate is more soluble in water than in toluene"

    The book answer is true, but I don't know how to compare it.

    I mean, sodium benzoate is ionic, and water is very polar, so the solubility of the salt in water should be great. Nevertheless sodium benzoate has a aromatic nucleus, that is the same of toluene, so they should share pretty much the same molecular interactions and one should reasonably dissolve another too. Am I thinking wrong? If not, how should I compare both of the solubilities?

    Thanks
    John
     
  2. jcsd
  3. Sep 10, 2012 #2
    Nope you're thinking too hard. If it is ionic in general it is soluble in polar solvents.

    Now there is a cutoff. A 500000 dalton hydrocarbon polymer with a single charged group is obviously not going to be soluble. Where is the cutoff? Hard to say.

    That requires computational chemistry.
     
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