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Homework Help: Unknown solutions!

  1. Oct 31, 2011 #1
    There are 3 beakers with solutions inside of the beakers A B and C, however the labels have fallen off!

    The labels of the solutions are: MgSO4, CaCl2, and AgNO3.

    Explain the steps you would use to determine which beaker has which solution inside of each of the three beakers.

    _______________________

    My first intuition is that you need to precipitate something, I just don't know what. :(
     
  2. jcsd
  3. Nov 1, 2011 #2

    Borek

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    Staff: Mentor

    Follow your intuition then.

    Are you allowed to use additional reagents, or can you use only the three listed? In the latter case I am not convinced all three solutions can be properly identified.
     
  4. Nov 1, 2011 #3
    We can do what ever we want with it! Well, what I think is that first we take a sample of each and add Ca 2+ ions (CaO) to each, and it should then create a precipitate of CaSO4. After that take additional samples from each and add sulphide ions (Na2S) to then form a precipitate of Ag2S.

    That's what I think, is this correct?
     
  5. Nov 2, 2011 #4

    Borek

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    Staff: Mentor

    CaO as a source of Ca2+? Think it over.

    Na2S will work, but silver can be detected much simpler, with much more common reagent.
     
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