When does Hydrogen act as an Oxidising Agent?

Hydrogen can behave as either an oxidising agent or a reducing agent depending on the substance with which it reacts. When hydrogen reacts with sodium (Na), it acts as an oxidising agent because it gains electrons from sodium, causing sodium to get oxidised. In this reaction, hydrogen is reduced to H⁻ (hydride ion), forming sodium hydride (NaH) — a classic example of hydrogen acting as an oxidising agent.

• Reaction with Sodium: 2Na + H₂ → 2NaH — here sodium loses electrons (gets oxidised) and hydrogen gains electrons (gets reduced), confirming hydrogen as oxidising agent
• Hydride Formation: Hydrogen accepts electrons from active metals like Na, K, Ca to form metal hydrides — this is its oxidising role
• Why Not Br₂: Bromine is itself a stronger oxidising agent — hydrogen acts as a reducing agent with halogens like Br₂, not an oxidising agent
• Why Not N₂: Hydrogen reacts with nitrogen to form ammonia (NH₃) in Haber's process — here hydrogen acts as a reducing agent
• Why Not O₃: Ozone is a powerful oxidising agent itself — hydrogen again acts as reducing agent in reactions with oxygen-based compounds