Question 95 from UPSC CSE 2015 - Science and Technology

Question

With reference to 'fuel cells' in which hydrogen-rich fuel and oxygen are used to generate electricity, consider the following statements:
1. If pure hydrogen is used as a fuel, the fuel cell emits heat and water as by-products.
2. Fuel cells can be used for powering buildings and not for small devices like laptop computers.
3. Fuel cells produce electricity in the form of Alternating Current (AC).
Which of the statements given above is/are correct?

Accepted Answer

Correct Option: A. 1 only

Strategy: - Evaluate Statement 1 for technical correctness regarding fuel cell chemistry.
- Evaluate Statement 2, recognizing that fuel cells are scalable and can be used in small devices.
- Evaluate Statement 3, noting that fuel cells output DC, not AC.
- Eliminate statements 2 and 3 based on technical inaccuracies.

Key Info: Fuel cells are electrochemical devices that convert the chemical energy of hydrogen (or other fuels) and oxygen directly into electricity, water, and heat.

The overall reaction for a hydrogen fuel cell is 2H2 + O2 → 2H2O. This process produces water and heat as harmless byproducts, with no pollutants generated if pure hydrogen is used.

Fuel cells inherently generate electricity as Direct Current (DC). An inverter is required to convert the DC output to Alternating Current (AC) if needed.

**Applications:**
- Vehicles, such as cars and buses.
- Stationary applications, including buildings and backup power systems.
- Small portable devices, like laptops and mobile phones.

Companies and research institutions are actively developing miniaturized fuel cells for electronics, with patents secured by major technology firms.

**Types of Fuel Cells:**
- Proton Exchange Membrane (PEM)
- Solid Oxide Fuel Cell (SOFC)
- Phosphoric Acid Fuel Cell (PAFC)

These types are tailored for different scales and purposes.

Answer

Option B: 2 and 3 only

Answer

Option C: 1 and 3 only

Answer

Option D: 1, 2, and 3