PPT Slide

Precipitation and Separation of Ions

• At any instant in time, Q = [Ba2+][SO42-].

  • If Q < Ksp, precipitation occurs until Q = Ksp.
  • If Q = Ksp, equilibrium exists.
  • If Q > Ksp, solid dissolves until Q = Ksp.

• Based on solubilities, ions can be selectively removed from solutions.

• Consider a mixture of Zn2+(aq) and Cu2+(aq). CuS (Ksp = 6 _ 10-37) is less soluble than ZnS (Ksp = 2 _ 10-25), CuS will be removed from solution before ZnS.

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