What is the only chemical product of a hydrogen-oxygen fuel cell?
Launching your learning experience…
Exam Season Offer 🎯 Sign up today & get 15% OFF on Yearly Plan
Practise IGCSE 0620 questions in the style of recent Extended past papers, organised by syllabus subtopic. Each set comes with an examiner-style mark scheme and a downloadable worksheet.
Everything students ask about Cambridge IGCSE 0620 Hydrogen-oxygen fuel cells Topical Past Papers.
Top questions students ask on this sub-topic
All rights reserved
©2026 Tutopiya
All resources on this platform are independently created by Tutopiya and have no endorsement from the International Baccalaureate Organization.
These Hydrogen-oxygen fuel cells Topical Past Paper Questions are written in the style of recent Cambridge IGCSE Chemistry 0620 Extended papers and grouped by the Electrochemistry (C4.2) section of the 2025–2027 syllabus. Use them to revise the exact skills examiners test in this part of the course.
Each question is graded Easy → Medium → Hard, plus an A★ Challenge for top-grade preparation. Tap a question to mark your own answer, then unlock the examiner-style mark scheme with model solutions and examiner tips. A printable Topical Past Papers worksheet is included so you can practise offline.
Describe how a hydrogen–oxygen fuel cell uses hydrogen and oxygen to produce electricity, with water as the only product. Compare advantages and disadvantages of hydrogen–oxygen fuel cells with petrol/diesel engines.
What is the only chemical product of a hydrogen-oxygen fuel cell?
A hydrogen-oxygen fuel cell is used to power an electric vehicle.
Write a balanced equation for the overall reaction that occurs inside the fuel cell.
[1 mark]State the type of energy conversion that occurs in a hydrogen-oxygen fuel cell.
[1 mark]Which of the following is NOT an advantage of a hydrogen-oxygen fuel cell over a petrol engine in a car?
Hydrogen-oxygen fuel cells are being developed as a power source for cars and buses.
State TWO environmental advantages of using a fuel cell in a vehicle instead of a petrol or diesel engine.
[2 marks]State ONE disadvantage of using a fuel cell as the power source for a car.
[1 mark]Compared with rechargeable batteries (like those used in standard electric vehicles), what is an advantage of using a hydrogen-oxygen fuel cell to power a vehicle?
Inside a hydrogen-oxygen fuel cell, hydrogen is supplied to the negative electrode and oxygen to the positive electrode. The two electrodes are separated by an electrolyte that allows ions to move.
At which electrode (positive or negative) is hydrogen oxidised? Briefly explain.
[1 mark]State what happens to the oxygen at the positive electrode (in terms of electron transfer).
[1 mark]Explain how the electrolyte completes the circuit inside the fuel cell.
[1 mark]State the maximum theoretical efficiency limit. (Choose: ~25%, ~60%, ~85%, ~100%.)
[1 mark]Hydrogen for fuel cells is typically produced in two main ways: (i) steam reforming of methane, CH₄ + H₂O → CO + 3H₂, and (ii) electrolysis of water.
Explain why hydrogen produced by steam reforming of methane is sometimes described as 'not truly clean', even though the fuel cell itself only emits water.
[1 mark]Suggest how electrolysis of water could provide a 'cleaner' source of hydrogen, and what one major condition is required for this to be truly carbon-neutral.
[2 marks]Why does a hydrogen-oxygen fuel cell achieve higher efficiency than a petrol engine for the same chemical energy input?