Fuel cells

Question 1

What does the electrolyte do in alkaline fuel cells?

Answer 1

• Facilitates the movement of OH- ions from the oxygen side to the hydrogen side. (contains a high conc of OH-)

Question 2

Which is the positive electrode in an alkaline fuel cell?

Answer 2

The oxygen side

Question 3

Which is the negative electrode in an alkaline fuel cell?

Answer 3

The hydrogen side.

Question 4

What is the reaction at the negative (hydrogen) electrode in a hydrogen-oxygen fuel cell?

Answer 4

H2 + 2OH- –> 2e- + 2H2O

Question 5

What is the reaction at the positive (oxygen) electrode in a hydrogen-oxygen fuel cell?

Answer 5

1/2 O2 + H2O + 2e- –> 2 OH-

Question 6

What is the full equation in a hydrogen fuel cell?

Answer 6

1/2 O2 + H2 –> H2O

Question 7

What other fuels can be used in fuel cells?

Answer 7

• Hydrogen rich fuels e.g methanol, which can also reduced oxygen to form water.

Question 8

What is the difference between acidic and alkaline fuel cells?

Answer 8

• Acidic electrolyte vs alkaline electrolyte.
• H+ or OH- ions flow to connect the two terminals.

Question 9

In what direction do H+ ions travel in an acidic fuel cell?

Answer 9

From H2 side to O2 side

Question 10

What reactions occur in an acidic hydrogen fuel cell?

Answer 10

H2 –> 2e- + 2H+
1/2O2 + 2H+ + 2e- –> H2O

Question 11

What are the pros of hydrogen fuel cells?

Answer 11

• only produce water
• more efficient than fossil fuel combustion

Question 12

What are the cons of H fuel cells?

Answer 12

• Hydrogen production uses fossil fuels.