UPSC Prelims 2024·GS1·science-and-technology·science and technology

Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?

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Last updated 8 Jul 2026, 4:39 pm IST
  1. AHydrogen peroxide
  2. BHydronium
  3. COxygen
  4. DWater vapourCorrect

Explanation

Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen generate electricity through an electrochemical reaction between hydrogen (H₂) and oxygen (O₂) from the air. The chemical reaction that occurs in the fuel cell is:

2H₂ (hydrogen) + O₂ (oxygen) → 2H₂O (water) + electricity + heat

The primary exhaust emission from the tailpipe of a hydrogen FCEV is water vapour. This makes FCEVs zero-emission vehicles at the point of use, as they only produce water.

  • Hydrogen peroxide (H₂O₂): A strong oxidizer, not a primary exhaust product.
  • Hydronium (H₃O⁺): An ion found in acidic solutions, not an exhaust gas.
  • Oxygen (O₂): A reactant in the fuel cell, taken from the air, not an emission.

Therefore, water vapour is the correct answer.

science-and-technology: Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?
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