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Science

Class 10 · Science & Environment

Real UPSC Prelims questions from 2016–2026, linked to this book. Try each one first, then open the answer. 2026 answers follow UPSC's provisional answer key.

Ch 4 · Carbon and its Compounds

Prelims 2024 · Q37

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

(a)Hydrogen peroxide
(b)Hydronium
(c)Oxygen
(d)Water vapour

Show answer

UPSC's answer: (d)

NCERT answers it: Class 10 Science, Ch 4 (Carbon and its Compounds).

The one fact NCERT doesn't give: A hydrogen fuel cell combines hydrogen with oxygen to make electricity, so a fuel-cell car's only tailpipe emissions are water vapour and warm air.

Class 10 Science, ch 4: a water molecule is made of one oxygen atom and two hydrogen atoms. With the fact, the exhaust is water vapour. Answer (d).

Hindi version: UPSC's official question paper (2024), question 37 ↗

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