Electrolysis

Question 1

Advantages of a hydrogen fuel cell

Answer 1

• Is a renewable source of energy as hydrogen is obtained from the electrolysis of water.
• Hydrogen fuel cells produce water as the only product of combustion of hydrogen. Water has no adverse effect (harmless) to human health.

Question 2

Disadvantages of a hydrogen fuel cell

Answer 2

• It is difficult to find a cheap source of hydrogen. Obtaining hydrogen from electrolysis is an expensive process.
• Hydrogen is currently obtained from non-renewable energy sources such as cracking petroleum.
• It is difficult to store and transport hydrogen safely as hydrogen is a highly flammable gas at room temperature and pressure. Hydrogen is often transported in high- pressure cylinders which can be dangerous to handle.

Question 3

What are some disadvantages of graphite as electrodes?

Answer 3

• Graphite will react with oxygen gas (produced at the anode) under high temperature to produce carbon dioxide.
• Graphite anodes need to be periodically replaced.

Question 4

What are some disadvantages of using platinum as electrodes.

Answer 4

Lower melting point than
graphite
* Might melt when used in the
electrolysis of molten ionic
compounds

Question 5

What is reduced and oxidised in hydrogen -oxygen fuel cells?

Answer 5

In hydrogen-oxygen fuel cell, oxygen is reduced to form hydroxide ions at the cathode and hydrogen is oxidised to form water at the anode

Question 6

What kind of reaction is in hydrogen fuel cells?

Answer 6

Exothermic