Question

Fuel cell, using hydrogen and oxygen as fuels,
A. has been used in spaceship
B. has as efficiency of 40% to produce electricity
C. uses aluminium as catalysts
D. is eco-friendly
E. is actually a type of Galvanic cell only

• A. A,B,C only
• B. A,B,D only
• C. A,B,D,E only
• D. A,D,E only

Answer 1

The Correct Option is D

A fuel cell, specifically using hydrogen and oxygen, has found applications in spaceships due to its capability to provide electricity in a lightweight, efficient form. It does not use aluminum as a catalyst but rather commonly uses platinum or other noble metals. Fuel cells operate in an eco-friendly manner, emitting only water as a by-product. Furthermore, they can be categorized as galvanic cells since they convert chemical energy directly into electrical energy.

Answer 2

Step 1: Understanding the concept of a fuel cell
A fuel cell is an electrochemical device that directly converts the chemical energy of a fuel (like hydrogen) and an oxidizing agent (like oxygen) into electrical energy, water, and heat. Unlike conventional cells, a fuel cell operates continuously as long as reactants are supplied.

Step 2: Working principle of hydrogen-oxygen fuel cell
In a hydrogen-oxygen fuel cell:
- Hydrogen gas is supplied at the anode, where it gets oxidized:
\[ 2H_2 \rightarrow 4H^+ + 4e^- \] - Oxygen gas is supplied at the cathode, where it gets reduced:
\[ O_2 + 4H^+ + 4e^- \rightarrow 2H_2O \] - The overall reaction is:
\[ 2H_2 + O_2 \rightarrow 2H_2O \] This reaction releases electrical energy and heat, with water being the only byproduct.

Step 3: Evaluate each given statement
A. Has been used in spaceship: Correct. Hydrogen-oxygen fuel cells have been used in space missions (e.g., Apollo program) to supply both electricity and drinking water.

B. Has efficiency of 40% to produce electricity: Incorrect. The hydrogen-oxygen fuel cell has an efficiency of about 60–70%, which is higher than typical thermal power systems (≈40%).

C. Uses aluminium as catalyst: Incorrect. The common catalysts used are platinum or nickel, not aluminium.

D. Is eco-friendly: Correct. The only product is water; no greenhouse gases or pollutants are released, making it environmentally friendly.

E. Is actually a type of Galvanic cell only: Correct. A fuel cell, like a Galvanic cell, produces electricity from spontaneous redox reactions but continuously operates as long as fuel is supplied.

Step 4: Conclusion
Therefore, the correct statements about the hydrogen-oxygen fuel cell are:

A, D, E only