Question

hydrogen fuel cells are a type of alternative energy. these cells are expensive, but they produce no air pollution. what is the only thing that these fuel cells produce? acid water

Explanation:

Hydrogen fuel cells combine hydrogen and oxygen. The chemical reaction in them produces electricity, heat, and water. Since they produce no air pollution (unlike many fossil - fuel - based energy sources), and among the given options, water is the non - polluting product. Acid is not a product of clean hydrogen fuel cell reactions.

Answer:

water