2024 GS Paper I, all questions
UPSC Prelims 2024 · GS Paper I
Question 37: Science and Technology
Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?
aHydrogen peroxide
bHydronium
cOxygen
dWater vapour
AnswerUPSC’s answer is (d).
A hydrogen fuel cell combines hydrogen from the tank with oxygen from the air to make electricity, and the only by-product is water. A Fuel Cell Electric Vehicle therefore has no carbon dioxide at the tailpipe; what comes out is water vapour. Remember: FCEVs emit only water vapour, which is why hydrogen is promoted as a clean transport fuel.
Why each option is right or wrong
- (a) Wrong: hydrogen peroxide is not formed in normal fuel cell operation.
- (b) Wrong: hydronium is an ion in solution, not an exhaust gas.
- (c) Wrong: the cell consumes oxygen; it is not an emission.
- (d) Right: hydrogen and oxygen combine to give water, emitted as vapour.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2024, General Studies Paper I, Series A. The paper on upsc.gov.in.