1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Chemical Equlibrium of BaCrO4

  1. Feb 9, 2015 #1
    1. The problem statement, all variables and given/known data
    Hi everyone,

    I'm trying to finish my lab report but I'm stuck on this question and don't even know how to start it. Could anyone let me know how to board it or a starting clue?

    I'm given these two equations

    1. BaCrO4 (s) <---> Ba2+ (aq) + CrO42- (aq)

    2. 2CrO42- (aq) + 2H+ (aq) <----> Cr2O72- (aq) + H2O (l)

    Question: How would you precipitate BaCrO4 from a solution of Ba(NO3)2 and K2Cr2O7 ? And I need to show it in chemical equations.

    2. Relevant equations


    3. The attempt at a solution

    I honestly have no clue...
     
  2. jcsd
  3. Feb 9, 2015 #2

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You're working on the chromate-dichromate equilibrium in another thread; can you apply that equilibrium to this problem?
     
  4. Feb 9, 2015 #3
    Sure, if I knew how to that is...:)
     
  5. Feb 10, 2015 #4

    Borek

    User Avatar

    Staff: Mentor

    Do you need low, or high concentration of CrO42- to precipitate BaCrO4?

    How does concentration of CrO42- depend on pH? (That's a direct conclusion of the question you posted in another thread, changing pH shifts the CrO42-/Cr2O72- equilibrium; how?)
     
  6. Feb 10, 2015 #5
    Hi,

    I was just looking at that and this is what I came up with: so I would need a high concentration of CrO42- to precipitate BaCrO4 and I can increase the concentration of CrO42- by lowering the concentration of H+ by adding NaOH so it will neutralize the H+. This way my equilibrium will shift to the left forming more CrO42-. Then by adding Ba(NO3)2...the NO3 would be a spectator ion but Ba2+ would form the BaCrO4 precipitate because BaCr2O7 is more soluble...would that be right?
     
  7. Feb 10, 2015 #6

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    It would.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Chemical Equlibrium of BaCrO4
  1. Acid-base equlibrium (Replies: 4)

  2. Chemical Kinetics (Replies: 1)

Loading...