H₂O₂ bleaches hair but also fuels rockets. Explain the dual chemistry. Step 1: As oxidiser: H₂O₂ + 2H⁺ + 2e⁻ → 2H₂O — steals electrons, bleaches melanin in hair. Step 2: As reducer: H₂O₂ → O₂ + 2H⁺: + 2e⁻ — gives electrons to stronger oxidisers (e.g., MnO₄⁻). Step 3: Decomposition 2H₂O₂ → 2H₂O + O₂ releases O₂ gas rapidly. Step 4: Concentrated H₂O₂ + fuel = rocket propellant (V-2, Soyuz use it)!