C5- Energy Chnages

Question 1

Give the half equations for the electrode reactions in a hydrogen fuel cell (4)

Answer 1

At negative electrode - H2 —> 2e- + 2H+
At positive electrode - 4H+ + O2 + 4e- —> 2H2O

Question 2

Give an advantage and a disadvantage of using hydrogen fuel cells to power an electric car (2)

Answer 2

Advantage = clean energy source, emitting only water as a byproduct
Disadvantage = limited hydrogen infrastructure, production of hydrogen often relies on energy intensive processes, reducing overall efficiency