Hydrogen Peroxide (H₂O₂)

Preparation of Hydrogen Peroxide:

• Industrially, It is prepared by the anthraquinone process, where anthraquinone is hydrogenated to form anthrahydroquinone, which reacts with oxygen to produce H2O2:

$\mathrm{C_6H_4(CO)_2(CH_2)_2 + H_2 \rightarrow C_6H_4(COH)_2(CH_2)_2}$​

$\mathrm{C_6H_4(COH)_2(CH_2)_2 + O_2 \rightarrow C_6H_4(CO)_2(CH_2)_2 + H_2O_2}$

Properties of Hydrogen Peroxide:

• Colorless liquid with a slightly sharp odor.
• Miscible with water in all proportions.
• Acts as a weak acid and strong oxidizing agent.
• Typically, available as a 3
• Chemical formula: H₂O₂.

Uses:

• As an antiseptic for cleaning wounds to prevent infection.
• As an oral rinse for mouth ulcers and gingivitis.
• In higher concentrations, used for sterilizing medical equipment.
• As a bleaching agent in the cosmetic industry.

Storage:

• Store in a cool, dark place, away from light and heat to prevent decomposition.
• Keep in a well-sealed, non-metallic container, typically brown or opaque to protect from light.

Assay of Hydrogen Peroxide (H₂O₂)

Purpose:

• To determine the concentration or purity of hydrogen peroxide using permanganate titration.

• Procedure:

  1. Prepare a Standard Solution:
     • Dissolve a known amount of potassium permanganate (KMnO₄) in water to create a solution of known concentration.
  2. Prepare the H₂O₂ Sample:
     • Dilute an accurate volume of the H₂O₂ sample with water, as concentrated H₂O₂ can be hazardous.
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  3. Add Acid:
     • Add a known volume of sulfuric acid (H₂SO₄) to the diluted H₂O₂ sample to create an acidic environment for the reaction.
  4. Titrate:
     • Slowly add the KMnO₄ solution to the acidic H₂O₂ solution while stirring.
     • The reaction between H₂O₂ and KMnO₄ occurs as follows:
     • The endpoint is reached when the pink color of KMnO₄ persists, indicating that all the H₂O₂ has reacted.
  5. Calculate the Concentration:
     • Measure the volume of KMnO₄ solution used in the titration.
     • Use the stoichiometry of the reaction to calculate the concentration or purity of the H₂O₂ sample.
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