Question

Phosphoric acid is preferred over sulphuric acid in preparing hydrogen peroxide from peroxides. Why?

Answer 1

In the preparation of H₂O₂ from barium peroxide and sulphuric acid, the use of sulphuric acid has a disadvantage as it catalyses the decomposition of H₂O₂ formed. In place of H₂O₂, weak acids like ortho phosphoric acid, carbonic acid are preferred. All heavy metal impurities present in BaO₂ are removed as insoluble phosphates and decomposition of H₂O₂ is prevented.