Question 16 from UPSC CSE 2024 - Environm ent

Question

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

IASCODEX · Accepted Answer

Correct Option: D. Water vapour

Strategy: *   Identify the core chemical process of hydrogen fuel cells: hydrogen and oxygen combine to generate electricity, with water as the sole byproduct.
*   Based on this, recognize that water vapor is the only emission consistent with the reaction.
*   Exclude other options (hydrogen peroxide, hydronium, oxygen) as they are either not typical byproducts or are reactants.

Key Info: ## Fuel Cell Electric Vehicles (FCEVs)

FCEVs use a proton-exchange membrane fuel cell to generate electricity. This process combines hydrogen gas (H2) from a tank with oxygen (O2) from the air.

### Emissions
-   The sole tailpipe emission is water (H2O), typically released as water vapor.
-   No air pollutants like nitrogen oxides, carbon monoxide, or particulates are produced.
-   Hydrogen peroxide (H2O2) and hydronium (H3O+) are not normal byproducts.
-   Oxygen is a reactant, not an exhaust product.

FCEVs offer an environmentally benign alternative to conventional internal combustion engine vehicles and battery electric vehicles.

IASCODEX · Answer

Option A: Hydrogen peroxide

IASCODEX · Answer

Option B: Hydronium

IASCODEX · Answer

Option C: Oxygen