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 aluminum as catalysts
D. is eco-friendly
E. is actually a type of Galvanic cell only
Choose the correct answer from the options given below:

Solution

Chemistry ma’am · 2 steps

Judge each statement on its own; the 40% figure belongs to thermal power plants, not fuel cells.

1. How it works. In the H₂–O₂ fuel cell, the gases bubble through porous carbon electrodes into hot aqueous KOH. Finely divided platinum or palladium in the electrodes speeds up the electrode reactions.

   2H₂(g) + O₂(g) → 2H₂O(l)

   Statement	True or false	Why
   A. Used in spaceships	True	It powered the Apollo missions, and the water it makes was used for drinking.
   B. 40% efficient	False	A fuel cell is about 70% efficient. About 40% is what thermal power plants reach.
   C. Aluminium catalyst	False	The catalyst is finely divided Pt or Pd, not Al.
   D. Eco-friendly	True	The only product is water, so it gives no polluting gases.
   E. A type of galvanic cell	True	It turns the energy of a spontaneous redox reaction straight into electricity, as every galvanic cell does.

2. So. Only A, D and E are correct, which is option (a).

The idea to keep. Remember the fuel cell facts as a set: H₂ and O₂ fuels, Pt or Pd catalyst, KOH electrolyte, about 70% efficiency, water as the only product, and a galvanic cell at heart.

Answer from the NTA final answer key. Solution by PrepWiser.