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Homework Help: Chem: Soluble with Insoluble: Will Reaction occur?

  1. Oct 6, 2008 #1
    1. The problem statement, all variables and given/known data

    Write the balanced net ionic equations for the reactions, if any that occur between:

    NiS(s) & HCl(aq)

    My attempt:

    NiS(s) + 2HCl(aq) -> NiCl2(aq) + H2S(s)

    NiS(s) + 2H + 2CL -> Ni(aq) + 2CL + H2S(s)

    NiS(s) + 2H(aq) -> Ni(aq) + H2S(s)

    My real question is, would NiS and HCl even react, as NiS is insoluable...
  2. jcsd
  3. Oct 6, 2008 #2


    User Avatar

    Staff: Mentor

    H2S is not solid.

    Ionic and net ionic reactions require that ions have actual charges.

    You are missing several (aq) symbols, but equations are - at least - properly balanced in terms of atoms.

    This is difficult question. Just because something is insoluble doesn't meant that it will not dissolve in acid or base - for example calcium carbonate, which is insoluble, will happily dissolve in hydrochloric acid with a lot of fizzling. Similar situation happens with many sulfides - they can be dissolved in hydrochloric acid. However, NiS is unique. It has two different forms. One dissolves easily, second can be dissolved only in the presence of strong oxidizing agents. The first one forms when you precipitate NiS, the second one - if NiS precipitate is left for at least several hours for so called aging. So both answers - that it will dissolve and that it will not - are right and wrong at the same time.
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