Thursday, April 21, 2022

Identification test for hydrogen peroxide

Learn the identification test for hydrogen peroxide through a laboratory experiment or practical.

Aim:

To perform identification test for hydrogen peroxide.

Reference: Indian Pharmacopoeia (IP)

Requirements:

Glasswares and miscellaneous:
Test tube, measuring cylinder, pipette, glass rod, volumetric flask, beaker, funnel, dropper, rubber stopper, test tube stand, test tube holder, balance, etc.

Chemicals:
Hydrogen peroxide (H2O2), sodium hydroxide (NaOH), potassium chromate (K2CrO4), sulphuric acid (H2SO4), ether ((C2H5)2O), etc.

Theory:

Identification tests are used to determine the drug's quality so that it can be used safely. Hydrogen peroxide is a reactive oxygen species with an oxygen–oxygen single bond. It is a colorless, odorless liquid having a bitter taste. It's a very pale blue liquid that's slightly more viscous than water in its purest state.

Hydrogen peroxide is an antiseptic and topical anti-infective agent used as an oxidizer, and bleaching agent. It is unstable, readily decomposing to oxygen and water with the release of heat.

Procedure of identification tests for hydrogen peroxide:

  • Add 01.00 ml dilute solution of NaOH to hydrogen peroxide and heat it. Because of decomposition, oxygen is evolved:
2H20 → 2H2O + O2
  • Acidify the hydrogen peroxide solution by adding 02.00 ml of a dilute solution of sulfuric acid. Add a drop solution of potassium chromate and 02.00 ml of ether. The formation of chromium pentoxide causes the ethereal layer to turn blue.
KC2rO4 + H2SO4 + 2H202 → CrO5 + K2SO4 + 3H2O

Result: 

The given sample is identified as hydrogen peroxide.


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