Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen ?
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Answer: D. A hydrogen fuel cell combines hydrogen with oxygen from the air to make electricity. The only product is water, so the tailpipe of a hydrogen fuel cell vehicle releases just water vapour (and some warm air).
Watch for: Students may think oxygen comes out because hydrogen 'burns', but oxygen is consumed and water is the product.
Why the other options are wrong
- A. Wrong because hydrogen peroxide is not produced in a fuel cell.
- B. Wrong because hydronium ions are not emitted as exhaust.
- C. Wrong because oxygen is used up in the cell, not released.
Source to check: US Department of Energy, Alternative Fuels Data Center, 'How Do Fuel Cell Electric Vehicles Work Using Hydrogen?' (afdc.energy.gov)
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.