Hydrogen peroxide was discovered in 1818 and first used for cotton bleaching in 1866, though its high costs limited industrial use until 1935. It is a colorless, corrosive liquid that is stable under acid conditions but decomposes rapidly under alkaline pH, requiring stabilizers like sodium silicate to control its decomposition rate. When activated by alkalis like sodium hydroxide or carbonates, hydrogen peroxide bleaches cotton through formation of reactive radicals rather than atmospheric oxygen.

1. Bleaching cotton with Hydrogen Peroxide

2. Discovery Discovered in 1818 Used for cotton bleaching 1866 High cost, Limited use Industrial use as bleaching agent 1935

3. Properties Colourless liquid Corrosive to skin Stable under acid pH Stabilized by phosphoric acid Activated under alkaline pH NaOH, Na2CO3, Trisodium phosphate alone or in combination may used as alkali for activation Decomposition in presence of alkali alone is very rapid Uneven bleaching

4. Stabilizer Compounds whioch control the rate of decomposition of H2O2 under alkaline conditions. Sodium silicate is the most common and economical stabilizer Other non silicate based stabilizers include Metal chelating agents like EDTA Decomposition products of protein MgCO3 and CaCO3 present in hard water Polyacrylates etc.

5. Mechanism of H2O2 bleaching Initial understanding 2 H2O2  2H2O + O2 Not correct because beaching not achieved by atmospheric oxygen Present understanding In presence of alkali H2O2 +OH  HO.