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O-7
Discard all solutions into your TOXIC WASTE beaker at your work station.
Part II: Titration of an unknown Hydrogen Peroxide, H2O2, solution
Obtain a bottle of an unknown solution that contains hydrogen peroxide, H2O2,
the concentration of
which will be within the range of 0.03 to 0.12 M. Record the number of the unknown on the
Observations Sheet. Pour about 15 mL of your unknown solution into a clean dry 50 mL beaker.
NOTE: Do not pipet from the bottle
containing the H2O2
unknown. Rinse your pipet first with
distilled water and then with a portion of the unknown H2O2 from the beaker to ensure that all the oxalic
acid solution is removed. Discard the remaining solution from the beaker and pour about 40 mL of
fresh unknown solution into the 50 mL beaker. Pipet 10.00 mL of this hydrogen peroxide solution into
a clean 200 mL Erlenmeyer flask. Add 1 mL of 6.0 M H2SO
4
to this solution. Titrate this sample with
the standardized KMnO
4
solution to the first permanent pale pink end point.
NOTE: This solution must not be heated prior to titration.
Repeat the titration on 10.00 mL samples of the unknown H2O2 until three consistent volumes (+ 0.1
mL) of titrant are obtained.
Discard all solutions into your TOXIC WASTE beaker and then empty your beaker into the
large toxic waste container in the fume hood.
Before leaving the laboratory, check to make sure that all of your equipment is clean, and in your
drawer. As well, all communal equipment must be cleaned and returned to the designated location in
the laboratory.
