Question

which of the following best explains the process of electricity generation in a hydrogen fuel cell?
a at the cathode, water reacts with oxygen to release hydrogen and heat. electricity is generated as the bonds form between hydrogen and oxygen. the by - product of the reaction is heat.
b at the cathode, hydrogen is reduced and then electrons flow to the anode to generate electricity. oxygen is produced at the cathode. oxygen and heat are the by - products of the reaction.
c at the anode, hydrogen is oxidized and electrons flow in a circuit to the cathode. at the cathode, oxygen reacts with the hydrogen to produce water. water and heat are by - products of the reaction.
d at the anode, hydrogen is oxidized and electrons pass through an electrolyte to the cathode. there, the protons react with water to produce oxygen. water and heat are by - products of the reaction.

Explanation:

In a hydrogen fuel cell, at the anode, hydrogen (\(H_2\)) is oxidized (\(H_2
ightarrow 2H^{+}+ 2e^{-}\)). The electrons flow through an external circuit to the cathode. At the cathode, oxygen (\(O_2\)) reacts with the hydrogen ions (\(H^{+}\)) and electrons (\(e^{-}\)) to produce water (\(O_2 + 4H^{+}+4e^{-}
ightarrow 2H_2O\)). Water and heat are the by - products.

• Option A: Water does not react with oxygen to release hydrogen in a fuel cell. The correct reaction is hydrogen and oxygen reacting to form water.
• Option B: Hydrogen is oxidized at the anode, not reduced at the cathode. And oxygen is consumed at the cathode, not produced.
• Option D: Electrons flow through an external circuit, not through the electrolyte (protons pass through the electrolyte). And at the cathode, oxygen reacts with hydrogen ions (not water reacting to produce oxygen).

Answer:

C. At the anode, hydrogen is oxidized and electrons flow in a circuit to the cathode. At the cathode, oxygen reacts with the hydrogen to produce water. Water and heat are by - products of the reaction.