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General Chemistry

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Concept: Fuel Cell Reactions

CHEM-FHEVYI

Fuel cells have seen use in technologies such as automobiles, fueling stations, portable power systems, and even space shuttles. Fuel cell operation is governed by electrochemical reactions that directly produce electric current. Space shuttles use an anion-exchange membrane fuel cell based on the reaction of oxygen and hydrogen to form water:

$${O}_{2} (g) + 2{H}_{2} (g) \xrightarrow [ ]{ } 2{H}_{2}O (l)$$

The fuel cell reaction occurs in alkaline conditions.

What are the correct balanced anode and cathode half-reactions?

A

Anode reaction: ${O}_{2} + 2{H}_{2}O + 4{e}^{-} \xrightarrow [ ]{ } 4O{H}^{-}$
Cathode reaction: $2{H}_{2} + 4O{H}^{-} \xrightarrow [ ]{ } 4{H}_{2}O + 4{e}^{-}$

B

Anode reaction: $2{H}_{2} + 4O{H}^{-} \xrightarrow [ ]{ } 4{H}_{2}O + 4{e}^{-}$
Cathode reaction: ${O}_{2} + 2{H}_{2}O + 4{e}^{-} \xrightarrow [ ]{ } 4O{H}^{-}$

C

Anode reaction: ${O}_{2} + {H}_{2}O + 2{e}^{-} \xrightarrow [ ]{ } 2O{H}^{-}$
Cathode reaction: ${H}_{2} + 2O{H}^{-} \xrightarrow [ ]{ } 2{H}_{2}O + 2{e}^{-}$

D

Anode reaction: ${H}_{2} + 2O{H}^{-} \xrightarrow [ ]{ } 2{H}_{2}O + 2{e}^{-}$
Cathode reaction: ${O}_{2} + {H}_{2}O + 2{e}^{-} \xrightarrow [ ]{ } 2O{H}^{-}$