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  5. Demo 25: Precipitation Reactions

Precipitation Reactions

Materials

3 Large Test Tubes

3 Erlenmeyer Flasks (to use as Test Tube racks)

Plastic 1 mL Pipets

Gloves and Goggles

      

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Procedure

Fill the test tube about halfway with the second solution of each pairing then using a 1 mL dropper add the first solution.  A precipate will form.

  1. 0.2M ferric nitrate is added dropwise to 1M sodium hydroxide. A red precipitate appears.
  2. 0.1M cobalt chloride is added dropwise to saturated calcium hydroxide. A blue precipitate appears.
  3. 0.2M potassium chromate is added dropwise to 0.05M lead acetate. A yellow precipitate appears.

      

Reactions

Fe(NO3)3(aq) + 3NaOH (aq) --> Fe(OH)3(s) + 3NaNO3(aq)

CoCl2(aq) + Ca(OH)2(aq) --> Co(OH)2(s) + CaCl2(aq)

K2CrO4(aq) + Pb(O2CCH3)2(aq) --> PbCrO4(s) + 2KO2CCH3(aq)

      

Waste Management

The solutions should be given to EH&S as waste.