Determining the Identity of an Unknown Contaminant in a Solution through the Use of a Designed Solubility Chart

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Determining the Identity of an Unknown Contaminant in a Solution through the Use of a Designed Solubility Chart

Purpose:

The purpose of this experiment was to design a solubility chart of seven anions and eleven cations to determine the unknown contaminant – either Al3+, Ca2+, Cu2+, Fe2+, Pb2+, Cl1- or SO42- – of a given solution of water.

Materials:
        

The materials utilized for part one:

  • Beakers
  • Droppers
  • Spot Plate
  • Test Tubes
  • Waste Beaker
  • Cation Solutions (Aluminum, Ammonium, Barium, Calcium, Copper, Iron, Magnesium, Silver, Sodium, Zinc and Lead ions)
  • Anion Solutions (Acetate, Bromide, Carbonate, Chloride, Hydroxide, Phosphate and Sulfate ions)

The materials utilized for part two:

  • Beakers
  • Droppers
  • Spot Plate
  • Test Tubes
  • Waste Beaker
  • Cation Solutions (Aluminum, Ammonium, Barium, Calcium, Copper, Iron, Magnesium, Silver, Sodium, Zinc and Lead ions)
  • Anion Solutions (Acetate, Bromide, Carbonate, Chloride, Hydroxide, Phosphate and Sulfate ions)
  • Unknown Solution (Sample 2)

Procedure:

The procedure utilized for part one to determine solubility chart for the experiment:

  1. All the eleven cations and seven anions were set up along the classroom for easy access.
  2. The spot plate was taken and all the spots were filled with 2 drops of Aluminum ion solution.
  3. Even though only seven spots were required, extra was filled for inconclusive results.
  4. Then all the anions were tested with one drop of each Acetate, Bromide, Carbonate, Chloride, Hydroxide, Phosphate and Sulfate ions were dropped in each of the spot wells.
  5. The results were recorded in Data Table 1.0 with an “I” for insoluble and “S” for soluble.
  6. The indecisive results were tested again in a small test tube for better clarity.
  7. Then steps 2-6 were repeated for the rest of the cation solutions: Ammonium, Barium, Calcium, Copper, Iron, Magnesium, Silver, Sodium, Zinc and Lead ion solutions.
  8. The waste materials were then discarded in the waste beaker and rinsed thoroughly after every use.

The procedure utilized for part two to determine the identity of the unknown solution through the use of the solubility chart:

  1. Approximately 3/4th of a test tube full of the unknown solution was received. The unknown solution was clear liquid labeled Sample 2.
  2. The unknown solution was tested for its solubility by first placing a few drops of the desired ion solution then two drops of the unknown solution as dropped into the well of the spot plate.
  3. Firstly, the solution was tested with the Lead ion (Pb 2+) solution as Lead ion was only soluble with Acetate and insoluble with the rest.
  4. If the unknown solution was soluble, then it would have to be a metal ion, if it was insoluble, then it was the chloride or sulphate ion.
  5. Since, the Lead ion solubility test was soluble, and then it was certain that the unknown solution was a metal ion either: Aluminum, Calcium, Copper, Iron or Lead ions.
  6. To determine the identity of the unknown solution, all the seven anion solutions were then placed into the wells of the spot plate in order to avoid confusion.
  7. Then two to three drops of the unknown solution was dropped in each of the wells on the spot plate.
  8. The solubility was recorded according to which anion solution it was reacted with.
  9. From that, the uniqueness of the ion in the water was determined from the solubility chart.
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Results and Observations

Data Table 1.0: The Solubility Chart Attained from the Results from Part One of the Experiment to Determine the Solubility of the Eleven Cations with Seven Anions

The table shows the solubility of the compounds in water of each cation and anion when reacted together. This solubility chart was then used to determine the Unknown solution (Sample 2).

Data Table 1.1: The Results Attained from the testing of each of the Anions with the Unknown Contaminant

This chart clearly shows that the ...

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