Alkaline hydrogen-oxygen fuel cell

Question 1

1. Hydrogen feed

Answer 1

Hydrogen fed in - reacts with OH- ions in solution in 9

2H2 (g) + 4OH– (aq) → 4H2O (l) + 4e– Eꝋ = -0.83 V

Question 2

2. Flow of electrons

Answer 2

Electrons produced in 1 travel through Pt electrode.
- Pt is a good conductor but is inert

Question 3

3. Component

Answer 3

Flow of electrons is used to power something

Question 4

4. Oxygen feed

Answer 4

Oxygen is fed in, reacts with water and the 4 electrons made in step 1 to make OH- ions

O2 (g) + 2H2O(l) + 4e– → 4OH– (aq) Eꝋ = +0.40 V

Question 5

5. Cathode

Answer 5

Electrons flow to Pt cathode

Question 6

Electrolyte

Answer 6

Made from KOH solution - carries OH- from cathode to anode

Question 7

7. Anode

Answer 7

Electrons flow from Pt anode to cathode

Question 8

8. Water emitted

Answer 8

Product of reaction (water) in step 1 is released into surroundings

Question 9

9. Movement of OH- ions

Answer 9

OH- ions produced from reaction 4 are carried towards the anode via the electrolyte

Question 10

Ion exchange membranes

Answer 10

These line the platinum electrodes and allow OH- ions to pass through but not hydrogen and gas