Assay of Hydrogen Peroxide by Permanganometry
Aim: To perform the assay of hydrogen peroxide by permanganometry.
Requirements:
- Apparatus: Beaker, Funnel, Pipette, Burrette.
- Chemicals: Hydrogen peroxide, Potassium permanganate.
Monograph: Hydrogen peroxide solution (20 Vol)
Molecular Weight 34.0
Hydrogen peroxide solution (6 percent); Dilute hydrogen peroxide solution.
Hydrogen peroxide solution (20 Vol) is an aqueous solution of hydrogen peroxide. It may contain a suitable stabilizing agent.
Hydrogen peroxide solution (20 Vol) contains not less than 5.0 percent w/v and not more than 7.0 percent w/v of H2O2, corresponding to about 20 times its volume of available oxygen.
Category: Antiseptic; deodorant.
Description: A clear, colorless liquid; odorless. It decomposes in contact with oxidizable organic matter and with certain metals and also if allowed to become alkaline.
Procedure:
(A) Standardisation of potassium permanganate: Preparation of potassium permanganate (0.02 M): Dissolve 158 × 2 i.e. 3.2 g of potassium permanganate in 900 ml of water heating in a water bath for 1 hour. Cooling, filtering through sintered glass, filter, add sufficient water to produce 1000 ml.
Procedure: To 25 ml of solution in glass stoppered flask add 2g of potassium iodide followed by 10 ml of 1 M sulphuric acid. Titrate the liberated iodine with 0.1 M sodium thiosulphate using 3 ml of starch solution added towards the end of titration as an indicator. Perform blank determination and make necessary corrections. Each ml of 0.02 M KMnO4 is equivalent to 0.003791 g of sodium thiosulphate.
(B) Assay: To 1.0 ml add 20 ml of sulphuric acid and titrate with 0.02 M potassium permanganate. 1 ml of 0.02 M potassium permanganate is equivalent to 0.001701 g of H2O2 or 0.56 ml of oxygen.
Observation table: (Standardization)
| Sr. No. | Parameters | Reading |
| 1. | Burette solution | Sodium thiosulphate |
| 2. | Conical flask solution | Potassium iodide |
| 3. | Indicator | Starch |
| 4. | Endpoint | Yellow to blue |
| Burette reading B.R (ml) | Trial 1 | Trial 2 | Trial 3 | Average (BR) |
Observation table: (Assay)
| Sr. No. | Parameters | Reading |
| 1. | Burette solution | Potassium permanganate |
| 2. | Conical flask solution | Sulphuric acid, hydrogen peroxide |
| 3. | Indicator | Potassium permanganate |
| 4. | Endpoint | Colorless to pink |
| Burette reading B.R (ml) | Trial 1 | Trial 2 | Trial 3 | Average (BR) |
Result: The% purity of hydrogen peroxide is …….
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