EXPT 5:
Qualitative Analysis
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Experiment 5 - Qualitative Analysis

Procedure:

Part A - Test for Lead (II) Ions

  1. Add about 20 drops of dilute hydrochloric acid (HCl) solution to about 10 drops of 0.5 M lead (II) nitrate, Pb(NO3)2 solution in a test tube and mix. Record your observations.
  2. Centrifuge and separate the precipitate from the solution. Discard the solution.
  3. Add about 2 mL of distilled water and stir to wash the precipitate. Centrifuge and separate the precipitate from the solution. Discard the solution.
  4. Add about the 3 mL of distilled water to precipitate and place the tube in a beaker of boiling water. Heat the mixture for about 2 minutes and stir occasionally. All the precipitate may not dissolve. Add more distilled water if necessary. Record your observations.
  5. Remove the tube from the beaker and add a few drops of 0.5 M potassium chromate, K2CrO4 solution.

    A yellow precipitate of lead (II) chromate, PbCrO4, confirms the presence of Pb2+ ions. Record your observations.

 

 



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