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Science29/09/2026

Electrolysis of Water: A Visual Explainer

A single flowchart showing how a DC current splits water at two platinum electrodes into hydrogen and oxygen gas — the reduction and oxidation half-reactions at each electrode, the fixed 2:1 gas ratio, and the confirmatory tests.

Electrolysis of Water: A Visual Explainer

📌 Revision Pointers

  • Cathode (−): Reduction — 2H⁺ + 2e⁻ → H₂(g).

  • Anode (+): Oxidation — 2H₂O → O₂(g) + 4H⁺ + 4e⁻.

  • Fixed volume ratio H₂ : O₂ = 2 : 1, confirmed by the 'pop' test (H₂) and the glowing-splint test (O₂).

Water splits into hydrogen at the cathode and oxygen at the anode, always in a fixed 2:1 volume ratio.

💭 Conclusion

Tests the electrolytic-cell polarity trap (cathode is NEGATIVE, unlike a galvanic cell) and links directly to the National Green Hydrogen Mission — a recurring Prelims/Mains connection.