Separation and Qualitative Determination of Cations and Anions

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Separation and Qualitative Determination of Cations and Anions Instructor’s Guide

Master Materials List (complete for 24 students working in pairs) Silver nitrate, AgNO3, 0.2 M, 100 mL*
Silver nitrate, AgNO3, 0.1 M, 100 mL*
Cupric nitrate, Cu(No3)2, .02 M, 100 mL*
Zinc nitrate, Zn(NO3)2, 0.2 M, 100 mL*
Ferric nitrate, Zn(NO3)2, 0.2 M, 100 mL*
Hydrochloric acid, HCl, 6 M, 125 mL*
Nitric acid, HNO3, 6 M, 125 mL*
Ammonia, NH3, 6 M, 125 mL*
Sulfuric acid, H2SO4, 6 M, 125 mL*
Acetic acid, CH3COOH, 6 M, 125 mL*
Sodium chloride, NaCl, 0.2 M, 100 mL*
Sodium carbonate, Na2CO3, 0.2 M, 100 mL*
Sodium hydroxide, 6 M, 100 mL*
Sodium sulfate, Na2SO4, 0.2 M, 100 mL*
Sodium nitrate, NaNO3, 0.2 M, 100 mL*
Barium chloride, BaCl2, 0.1 M, 100 mL*
Barium hydroxide, Ba(OH)2, 5 g*
Potassium thiocynate, KSCN, 0.1 M, 100 mL*
Potassium ferrocyanide, K4Fe(CN)6, 0.1 M, 140 mL*
Aluminum granules, Al, 50 g*
Beral-type pipets, 120*
*Materials included in kit

Additional Materials Needed
Beakers, 400-mL, 12
Beakers, 250-mL, 5-14
Centrifuges, 3
Dropper bottles, 15-30 mL, 96
Hot plates, 3-12
Litmus paper or pH paper
Microscope slides or watch glasses, 12
Spatulas, 12
Stirring rods, 12
Stoppers to fit test tubes, 72
Storage bottle, with cap, 125 mL
Test tubes, 13 X 100 mm, 72
Wire test tube holders, 12

Preparation of Solutions (for 12 student groups)
Note: 0.2 M solutions are provided so unknown solutions can be easily made. The 0.2 M solutions are also easier to ship and take up less room. Dilution the 0.2 M solutions to 0.05 M solutions does not have to quantitative. Use the markings on the beaker for measurements.

Solution of Four Cations
Prepare 100 mL of a 0.05 M solution of all the cations to be tested by adding 25 mL of each of the following solutions to a clean 250-mL beaker. 0.2 M silver nitrate, AgNO3
0.2 M cupric nitrate, Cu(NO)3
0.2 M zinc nitrate, Zn(NO3)2
0.2 M ferric nitrate, Fe(NO3)3

Mix the solution, dispense in 12 clean 13 X 100 mm test tubes, and a stopper the test tubes. Label as known cation solution.

Unknown Cation Solutions
Prepare unknown cation solutions for the students to analyze from the four 0.2 M stock solutions of cations. Any combination of these four cations may be prepared. Using a graduated Beral-type pipet, add 2 mL of each ion selected for the unknown to a clean 13 X 100 mm test tube, then add distilled water to create a total volume of 8 mL. Stopper the test tube. Some suggested combinations appear on the table below.

|Unknown No. |Ag+ |Cu2+ |Zn2+ |Fe3+ | |1 |X |X |X | | |2 | |X |X |X | |3 |X | |X |X | |4 |X |X | |X | |5 |X | | |X | |6 | |X | |X | |7 | |X |X | | |8 |X |X | | | |9 |X | |X | | |10 | | |X |X | |11 |X |X |X |X |

Solution of Four Anions
Prepare 100 mL of a 0.05 M solution of all the anions to be tested by adding 25 mL of each of the following solutions to a clean 250-mL beaker. 0.2 M sodium chloride, NaCl
0.2 M sodium carbonate, Na2CO3
0.2 M sodium nitrate, NaNO3
0.2 M...
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