Question

A small amount of phosphoric acid or glycerol or acetanilide
is added in H2O2 during its storage. Explain. ​

Answer 1

Answer:

From sodium peroxide (Merck’s method)

Calculated amount of sodium peroxide (Na2O2) is gradually added to an ice-cold solution of 20% H2SO4 in small lots with constant stiring.

Na2O2 + H2SO4 → Na2SO4 + H2O2

Upon cooling, crystals of Na2SO4.10H2O separate out and the resulting solution contains about 30% H2O2. The solution also contains some dissolved Na2SO4, but it does not interfere with the reactions of H2O2. A pure sample of H2O2 may, however, be prepared by vacuum distillation.

2. From barium peroxide-Laboratory method of preparation.

Hydrogen peroxide is prepared from barium peroxide by the following methods:

(a) By the action of dilute sulphuric acid. Apaste of hydrated barium peroxide (BaO2.8H2O) is prepared in ice – cold water and then added slowly to an ice-cold solution of 20% H2SO4.

BaO2.8H2O + H2SO4 → BaSO4 + H2O2 + 8H2O

The white precipitate of BaSO4 is removed by filtration leaving behind a dilute solution (5%) of H2O2. In this method, anhydrous barium peroxide can not used since the precipitated BaSO4 forms a protective layer around unreacted barium peroxide thereby preventing the further reaction

Answer 2

Answer:

Decomposition.

Explanation:

The decomposition of hydrogen peroxide is retarded in the presence of glycerine and alcohol. To prevent decomposition, hydrogen peroxide is stored in paraffin wax-coated plastic or teflon bottles. A small amount of acid, glycerol, alcohol, acetamide and phosphoric acid are often used as stabilizers to check the decomposition.