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Double salt

  1. Feb 27, 2010 #1

    elitewarr

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    How does double salt reactions work?

    Let's say, Cu(NH4)2(SO4)2 + NaOH --> ??
    OR maybe Cu(NH4)2(SO4)2 + BaCl2 --> ?

    Thanks.
     
    elitewarr, Feb 27, 2010
  2. jcsd
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  3. Feb 28, 2010 #2

    Borek

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    Staff: Mentor

    Think about each pair of ions seperately.

    --
    methods
     
    Borek, Feb 28, 2010
  4. Mar 1, 2010 #3

    elitewarr

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    So for the first equation, Cu(NH4)2(SO4)2 + NaOH gives NH3 + CuSO4 + Na2(SO4) + H2O?
    Cu(NH4)2(SO4)2 + BaCl2 will give NH3 + BaSO4 + CuCl2 ?
     
    elitewarr, Mar 1, 2010
  5. Mar 1, 2010 #4

    Borek

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    Staff: Mentor

    Do you know what net ionic reaction is?

    You are partially on the right track, partially wrong.

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    methods
     
    Borek, Mar 1, 2010
  6. Mar 1, 2010 #5

    elitewarr

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    Yes. I know what is ionic equation.
    So, Cu(NH4)2(SO4)2 break down becomes Cu2+ + 2NH4+ + 2SO4 2-
    NaOH will be Na+ and OH-.
    So OH- + NH4+ --> NH4OH --> NH3 + H2O ?
    and Cu2+ + 2SO4 2- + Na+ --> CuSO4 and Na2SO4?
     
    elitewarr, Mar 1, 2010
  7. Mar 1, 2010 #6

    Borek

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    Staff: Mentor

    What you wrote seems to be suggesting that two salts precipitated - that's not the case. If mixed, all three ions are just spectators.

    However, one of them can react with OH- and NH3...

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    Borek, Mar 1, 2010
  8. Mar 1, 2010 #7

    elitewarr

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    So Cu2+ will react with OH- ? But how do I know which ion will react?
     
    elitewarr, Mar 1, 2010
  9. Mar 1, 2010 #8

    Borek

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    Staff: Mentor

    Solubility rules - what do you know about solubility of hydroxides?

    However, this is more complicated. Ammonia is a good complexing agent and it easily reacts with copper. I am afraid exact outcome depends on the amount of reactants used.

    --
    methods
     
    Borek, Mar 1, 2010
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