Question

hydrogen fuel cells are a promising source of energy. which of these is the \waste\ product produced by a hydrogen fuel cell? argon silver helium water

Explanation:

Hydrogen fuel cells work by combining hydrogen and oxygen to produce electricity. The chemical reaction in a hydrogen fuel cell is \( 2H_2 + O_2
ightarrow 2H_2O \), so the waste product is water. Argon, silver, and helium are not products of this reaction.

Answer:

water (the option with "water" as the text, assuming the options are presented as radio buttons and we identify the correct one as the waste product from hydrogen fuel cell operation)