37
Question 37
Which one of the following is the exhaust pipe
emission from Fuel Cell Electric Vehicles,
powered by hydrogen ?
AOptions
A
A) Hydrogen peroxide
B
B) Hydronium
C
C) Oxygen
D
D) Water vapour
BSolution
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.
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.
CStrategy
Understand the basic chemical reaction within hydrogen fuel cells. It's essentially the reverse of electrolysis. Focus on the inputs (hydrogen, oxygen) and outputs (water, electricity, heat). This is a common point emphasized in clean energy discussions.
DSyllabus Analysis
Science & Technology: Energy (Fuel Cells, Hydrogen Economy), Environment (Clean Transportation).
EQuestion Analysis
This is a factual question from Science & Technology, specifically on clean energy and transportation. The fundamental reaction of hydrogen fuel cells yielding water is a key concept in this area. Easy difficulty.