Question

Write two advantages of hydrogen - oxygen fuel cell.

Hint:

Hydrogen is often called the "fuel of the future" because of its high energy density and low environmental impact when used in fuel cells.

Answer 1

Step 1: Understanding the Concept:
A fuel cell converts the chemical energy of a fuel (hydrogen) and an oxidant (oxygen) directly into electrical energy through redox reactions.
Step 2: Detailed Explanation:
Two major advantages are:
1. High Efficiency: Unlike thermal power plants that have an efficiency of about \( 40% \), fuel cells are much more efficient, converting about \( 70% \) of chemical energy into electricity. This is because they do not involve a heat engine cycle (Carnot cycle limitation).
2. Environmentally Friendly: The only byproduct of the reaction is water (\( 2H_2 + O_2 \rightarrow 2H_2O \)). It does not emit harmful gases like \( CO_2, SO_2, \) or nitrogen oxides, making it a "green" power source. This water can even be purified and used by astronauts in space missions (e.g., Apollo mission).
Step 3: Final Answer:
The advantages are high thermodynamic efficiency and the production of water as the sole non-polluting product.