J Ion Short Report Template

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Carleton University *

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1001

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Chemistry

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Feb 20, 2024

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docx

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Uploaded by CaptainTitanium13383

Ion Exchange Chromatography (Ion) Purpose The purpose of the lab is to apply the Ion-Exchange Chromatography methods for the separation of both positively charged ions (cations) and negatively charged ions (anions) in a solution that includes Cu2+, Na+, CrO42-, and Cl-.

Procedure Preparation 1. First, make sure that the two solutions (cations and anions) are always hydrated, so always remain a few centimeters of water above the solutes 2. Drain the water from the column. Open the tap a little to make sure that water goes out by one drop per second. into a beaker until the level of the water is several millimeters above the resin. 3. Weigh out ~1.0 g CuCl2  2H2O and ~0.5 g Na2CrO4 in separate small beakers. Dissolve each solid in about 20 mL of distilled water. 4. Mix the two solutions in a 100 mL beaker. Add 6 drops of HCl and dissolve it until the solution the cloudy precipitation and becomes translucid. 5. Make up the sample solution to ~50 mL with distilled water and determine the pH of the solution with pH paper. Adsorption of Ions 1. Measure 10 mL of the solution, and add it to the cation exchange column. Collect the eluate (Ec) in a beaker. 2. Add 40 mL of distilled water to the column and collect all the eluate in the same beaker. 3. Do the same with anion column. Then you will find (Ea) 4. Determine the pH of both eluates with pH paper. Elution of Cations and Anions 1. Obtain 40 mL of 1.0 M HCl and 40 mL of 3.0 M HCl. 2. Place a clean beaker under the cation exchange column and elute the column with 40 mL of l.0 M HCl (Ec1) 3. Replace the beaker with a second clean one. Elute the column with 40 mL increments of 3.0 M HCl until the eluate changes color. (Ec2) 4. Proceed for the anion column as for cations, but using first 30 ml of 0.06 M NH3(aq) for (Ea1), and then, replace the beaker with a second clean one and use 50 ml of 3.0 M NH3(aq) for (Ea2) until the eluate changes color. Column Regeneration 1. Wash the cation column with 70 mL of 3 M HCl into the column and drain off the acid approximately one drop per sec. 2. Add 250 ml of distilled water to the cation column. Wash the resin in this manner until the washings are basic to methyl orange.

3. Wash the anion column using 70 mL of 3 M NH3(aq) 4. Wash the column with 250 ml of distilled water until the washings are acidic to phenolphthalein. Identification of Ions Cation: Na+ To clean a platinum wire, heat it until it turns red, then dip it into concentrated HCl. After cleaning, dip the wire into the test solution( Ec1,Ec2). Cu2+ Place 5 drops of the solution in a test tube. Make it acidic by adding around one dropper full of 5 M acetic acid. Then, add 2 drops of 0.2 M K4Fe(CN)6 from the dropper bottles. When you see a red solid forming, it means there's copper in the solution. Anion: Cl− Put 5 or 6 drops of the solution into a test tube. Make it acidic by adding about 1 drop of 6 M HNO3 and then add 2 drops of 0.2 M AgNO3 solution. The formation of a white, powdery solid confirms the presence of chloride as shown by the reaction: CrO4 2− Take 1 mL of the solution in a test tube and make it slightly acidic by adding a full dropper of 6 M HNO3. Then, add a full dropper of ether and 1 or 2 drops of 3% H2O2. Stir the mixture thoroughly and allow it to. Observations

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Input the observations you have made from the video and give each table a detailed yet short title. Table 1: Cation (Ec) and anion (Ea) solutions observation Solution Colour observed Ion mixture Greenish Ec Yellow Ea Colorless Ec 1 Colourless Ec 2 Light blue Ea 1 Colourless Ea 2 yellow Ec eluate - ion mixture that goes through the cation column. Ec1 eluate – Ec that was washed with 40 mL of l.0 M HCl Ec2 eluate- Ec1 that was washed with 40 mL of 3.0 M HCl Ea eluate- Ec that goes through the anion column. Ea1 eluate – Ea that was washed with 40 mL of 0.06 M NH3(aq) Ea2 eluate- Ea1 that was washed with 40 mL of 3.0 M NH3(aq) Table 2: Solutions and their pH Solution pH observed (colour of the pH paper and approximate numerical equivalent) Ion mixture pH pepper color- red pH-2.0 Ec pH pepper color- red pH-2.0 Ea pH paper color- orange pH-7.0

Table 3: Cation and Anion test to determine the completeness of separation. Test performed Fraction from the ion exchange column Observation from test Flame test Ec 1 Color of flame- orange Ec 2 Color of flame- Green-orange Copper test Ec 1 brownish Ec 2 Dark brown Chloride test Ea 1 Cloudy white Ea 2 Light green- translucent Chromate test Ea 1 Transparent-colorless Ea 2 Transparent-colorless

Results Table 4: Ions that are presented in each solution based on their color. Fraction from the ion exchange column Ion(s) present Ec 1 Na+ Ec 2 Cu2+ Ea 1 Cl− Ea 2 CrO42− Discussion Ionic affinity directly depends on the force with which it is attracted to the resin. Based on the experiment, I can say that Na+ <Cu2+, since to separate N+ cations from the column we used 1M HCl, and to separate Cu2+ we used the same hydrochloric acid with a higher concentration of 3M. The trend can be explained by the fact that the greater charge of Cu2+ affects its flow rate through the column due to greater attraction to the electrolytes in the resin. This is confirmed by the flame test, which did not reveal the presence of Cu2+ in the Ec1 solution. The same thing happens with the anions Cl-<CrO42-. To separate CrO42− from the cation column, we used a higher concentration of the base NH3, so its affinity is greater than that of Cl−. Some of the sources of error may be that we do not lower the solution from the last resin wash, we do this to ensure that the resin does not dry out, it is mixed with new solutions and thus the results cannot be reliable. so accurate. For perfect separation, columns should be thoroughly washed between each run. The pH test shows that the Ec solution is acidic (pH=2) and has a bright red color. This is because the ionic mixture flew through the RSO3-H+ cation exchange acid resin and water was drained through the column. We got the result that the H+ ion from the resin combines with H2O to form the acid H30, which was collected in the beaker Ec, and this results in an acidic solution of Ph in Ec. When the Ec mixture flew through the R4N+OH anionic column and the water was drained through the anionic column, the H30 molecules in Ec combined with the OH in the resin and returned to the neutral aqueous state in Ea. So, the final pH of Ea is about 7.

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Conclusion Holding the tests to determine the presence of Na+ in Ec1, Cu2+ in Ec2, Cl- in Ea1, and Cro4 -2 in Ea2 all went successfully and showed that the presence of the ions are respective to the beaker where they must be after the Ion Exchange Chromatography process. The ion separation test shows how individual ions can separate from the mixture by washing them with different concentrations of acid/ base.