Learn about the assay of hydrogen peroxide solution (H2O2) through a laboratory experiment or practical.
Aim:
To perform the assay of hydrogen peroxides using standard 0.1 N KMnO4 solution by permanganometry (20 Vol).
Requirements:
Glasswares: Burette, burette stand, conical flask, volumetric pipette, beaker, volumetric flask, funnel, glass rod, and wash bottle, etc.
Chemicals: LR grade potassium permanganate (KMNO4), hydrogen peroxide (H2O2), and sulphuric acid (H2SO4), etc.
Apparatus: Digital/analytical balance, and Ultrasonicator.
Principle of hydrogen peroxide assay:
As an oxidizing agent, hydrogen peroxide is used. The assay of hydrogen peroxide solution is based upon the oxidation-reduction (permanganometry) titration. It gets oxidized to water and oxygen when titrated with a strong oxidizing agent in an acidified solution. The presence of hydrogen peroxide in an H2SO4-acidified solution is used to titrate the strength of KMnO4. Potassium permanganate works as a self-indicator and may be used to determine the endpoint by the appearance of permanent pink color.
The following is the reaction that is involved in this titration.
Preparation and standardization of 0.1 N KMn04:
Click here to get the procedure of preparation and standardization of potassium permanganate solution (0.1 N).
Preparation of 5N sulphuric acid solution:
Take 13.58 ml of sulfuric acid (H2SO4) using a pipette, dilute in 100 ml of distilled water in a volumetric flask, and properly mixing it.
Titration procedure:
- All glassware should be cleaned and dried according to standard laboratory procedures.
- Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
- Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
- Remove air bubbles from the burette and adjust the reading to zero.
- Take 10.00 ml of hydrogen peroxide using a pipette, dilute in 250 ml of distilled water in a volumetric flask, and properly mixing it.
- Take 25.00 ml of prepared dilution, pour into a conical flask and add 05.00 ml of sulphuric acid solution (5 N).
- Titrate the sample solution with potassium permanganate solution until the endpoint is reached.
- When the solution is swirled for up to 10 seconds, a pink color appears and fades, indicates that the endpoint is approaching. The actual endpoint of the titration is indicated by a pink color that lasts longer than 30 seconds.
- To get accurate results, repeat the titration three times.
- Properly record the readings of the burette.
- Take their mean and calculate the normality of hydrogen peroxide.
Observation table:-
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
|
|
|
|
2 |
|
|
|
|
|
3 |
|
|
|
|
|
Mean: |
|||
Calculations:
g/100 ml of H2O2 = V x E x N x 100 / 10
Where,
V is the volume of KMn04 used
E is an equivalent factor
N is the normality of KMnO4
For 1 ml of 0.1 N KMnO4, the equivalent factor of H2O2 is 0.0001701.
Result:
The given sample of hydrogen peroxide solution contains ___g/100 ml of H2O2.
Commonly asked quetions of the assay of of H2O2 are as follows.
Which indicator is used in the assay of hydrogen peroxide?
Potassium permanganate is a self-indicator, hence there is no indication is required in the hydrogen peroxide assay by permanganometry.
What is hydrogen peroxide used for in chemistry?
Hydrogen peroxide is mainly used in chemistry as an oxidizer, antiseptic, and bleaching agent.
How do you test hydrogen peroxide?
Titration, light detection, and chromatography are among the several methods for testing hydrogen peroxide.
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