Fuel Cells NEET Questions

Physical Chemistry - Redox Reactions and Electrochemistry

Fuel Cells MCQ Questions


13.
The product formed in a hydrogen-oxygen fuel cell is:
A.
Hydrogen peroxide
B.
Oxygen
C.
Water
D.
Carbon dioxide
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ANSWER :
C. Water
14.
In an acidic-electrolyte H⁺/PEM fuel cell, the cathode half-reaction is:
A.
H₂ → 2H⁺ + 2e⁻
B.
O₂ + 2H₂O + 4e⁻ → 4OH⁻
C.
O₂ + 4H⁺ + 4e⁻ → 2H₂O
D.
2H⁺ + 2e⁻ → H₂
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ANSWER :
C. O₂ + 4H⁺ + 4e⁻ → 2H₂O
15.
The standard EMF (E°cell) of the H₂-O₂ fuel cell at 298 K is approximately:
A.
2.10 V
B.
0.76 V
C.
0.34 V
D.
1.23 V
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ANSWER :
D. 1.23 V
16.
The relationship between EMF (E°cell) and standard Gibbs free energy change (ΔG°) for a fuel cell is:
A.
ΔG° = +nFE°cell
B.
ΔG° = −nFE°cell
C.
ΔG° = E°cell/(nF)
D.
ΔG° = nF/E°cell
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ANSWER :
B. ΔG° = −nFE°cell
17.
Why is the EMF of an actual H₂-O₂ fuel cell less than 1.23 V under operating conditions?
A.
Because of overpotentials, internal resistance, and slow kinetics of the electrode reactions
B.
Because water decomposes the fuel
C.
Because the electrolyte does not conduct electricity
D.
Because the reactants are not present in stoichiometric ratio
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ANSWER :
A. Because of overpotentials, internal resistance, and slow kinetics of the electrode reactions
18.
Compared to conventional thermal power plants, fuel cells have:
A.
Zero efficiency until very high temperatures
B.
Higher energy conversion efficiency (~70% or more)
C.
Lower energy conversion efficiency (~10%)
D.
Equal efficiency (~40%)
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ANSWER :
B. Higher energy conversion efficiency (~70% or more)