Submission of Proposal under Star College Scheme

Equipment/Materials:
0.02 M KI solution, 0.02 M K₂S₂O₈ solution, distilled water, spectrophotometer, cuvettes, 10 mL graduated pipette, 2 small test tubes, parafilm, tissue paper, etc.


Procedure:
1. Switch on the spectrophotometer and set the wavelength to 350 nm.
2. Place 2 ml of KI and 2 ml of distilled water into a cuvette to serve as blank. Cover with a piece of parafilm and invert several times to mix.
3. Insert the blank into the spectrophotometer. Set the absorbance to zero.
4. Place the required amount of KI and water into a cuvette and place the required amount of potassium persulphate into a small test tube (as given in the following table).

	Set – 1	Set – 2	Set – 3	Set – 4
Vol. KI (cm^3)	1	2	1	2
Vol. H2O (cm^3)	2	1	1	0
Vol. K2S2O8 (cm^3)	1	1	2	2

5. Quickly pour the contents of the test tube into the cuvette (start the timer immediately at the instant the liquid are mixed). Cover the cuvette with parafilm and invert three times.

6. Insert the cuvette in the sample compartment. Record the absorbance every 15 seconds in the data table. Consider the absorbance at time 0 to be 0.
7. When the run is complete, remove the cuvette and clean thoroughly.
8. Repeat steps 4-7 for remaining three sets of solutions. Only mix up the components for one set at a time.
9. Plot absorbance versus time and determine the slope of each run. Plot all the graphs on the same piece of paper (use a different colour of ink for each set).


Data table: