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O-5
REAGENTS AND EQUIPMENT
H2C2O
4
2 H2O (oxalic acid dihydrate)
100 mL volumetric flask
unknown H2O2 (hydrogen peroxide) solution
50 mL buret
0.01xx M KMnO
4
(potassium permanganate)
hot plate
6.0 M H2SO
4
(sulfuric acid)
10 mL volumetric pipet
pipet bulb
EXPERIMENTAL PROCEDURE
NOTE: Potassium permanganate, KMnO
4
, solutions will stain clothing and skin. Keep this in mind as
you prepare to come to the laboratory.
Prepare a “toxic waste” beaker for use at your workstation.
Part I: Standardization of the potassium permanganate, KMnO
4
, solution
Using the correct weighing technique obtain on an analytical balance enough oxalic acid dihydrate to
make up 100 mL of approximately 0.1000 M solution. (~ 1.100 g H2C2O
4
2 H2O)
Note: The mass does not have to be exactly what is calculated, however, you need to know
the exact mass to + 0.001 g so that the molarity of the solution can be calculated
accurately.
Add approximately 25 mL of deionized water and 15 mL of 6.0 M H2SO
4
to the
oxalic acid dihydrate. Warm the solution slightly on a hot plate to dissolve the oxalic acid. This solution
must be transferred QUANTITATIVELY to a 100 mL volumetric flask (See manual page 21). Do
this by pouring the solution through a funnel into the volumetric flask. Then wash the beaker with about
10 mL of distilled water and pour this washing through the funnel into the flask. Repeat this rinsing
three more times to ensure all of the oxalic acid has been transferred to the volumetric flask.
Carefully fill the volumetric flask to the mark using distilled water to prepare 100.0 mL of the
standardized oxalic acid solution. Use a Pasteur pipet to add water for the final volume
adjustment. Cover and seal the volumetric flask with a plastic cap and mix the solution thoroughly
so that it is a uniform concentration. Do this by repeatedly inverting and shaking the flask.
