Experimental procedure (ions)

Start by gathering the materials required for the experiment. Record your findings in a table.

1. Use a pencil to mark a line 3 cm from the end of the Whatman filter paper. This is the reference line.

2. Using a finely drawn capillary, put one spot of the lead cadmium solution on the reference line. Label the spot under the reference line and make a note of the label in your lab book.

3. Hang the filter paper in a jar containing 20 mL of a mixture of ethanol, 6 M HNO₃, and distilled water, in the ratio 8:1:1. The paper should hang so the solvent does not touch the reference line.

4. Keep the jar as still as possible until the mobile phase has gone up two thirds the length of the paper.

5. Remove the filter paper from the jar. Use a pencil to mark the solvent front.

6. The developer ammonium sulfide is prepared by passing H₂S gas through a mixture containing 100 mL of water and 10 mL of liquor ammonia for about 45 minutes.

7. Spray the ammonium sulfide solution on the chromatography paper to obtain yellow and black spots. Markt the positions of the spots with a pencil, and allow the paper to dry.

8. Measure the distance traveled by the solvent front and the center of the spots with respect to the reference line.

9. Calculate the R_f value of the different spots. Use the equation found here.

References:

• NCERT Chromatography handbook