Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?
- Hydrogen peroxide
- Hydronium
- Oxygen
- Water vapour
Show answer and solution
Correct answer: D. Water vapour
Answer: D. The exhaust emission from a hydrogen Fuel Cell Electric Vehicle is WATER VAPOUR.
In a hydrogen FCEV, hydrogen (H2) from the fuel tank combines with oxygen (O2) from the air at the fuel cell's catalyst surface. The electrochemical reaction is: 2 H2 + O2 -> 2 H2O + electricity.
The only chemical product leaving the exhaust is water (released as vapour due to operating temperature). This zero-emission profile is the main environmental selling point of FCEVs over internal combustion engines.
Distractors fail: (A) Hydrogen peroxide is not formed under normal fuel cell operation.
(B) Hydronium (H3O+) is a transient species in the electrolyte membrane, not exhaust.
(C) Oxygen is consumed, not emitted.
Source: Ministry of New and Renewable Energy + IEA Hydrogen Technology Roadmap.