Hydrogen as a Fuel (WJEC GCSE Chemistry: Combined Science)

• An alternative fuel to fossil fuels is hydrogen 
• Hydrogen is used in rocket engines and in fuel cells to power some cars and buses
• It reacts with oxygen in an exothermic reaction to produce water

hydrogen   +   oxygen   →   water

2H₂ + O₂ → 2H₂O

• Hydrogen has a series of advantages and disadvantages regarding its use as a fuel

Advantages

• The hydrogen is produced from water so the process is renewable
• Hydrogen only produces water on combustion, no other product is formed
  • Burning hydrogen therefore does not contribute towards global warming or acid rain

Disadvantages:

• Requires large amounts of electricity to produce the hydrogen from water 
  • The hydrogen is obtained by electrolysis
• Difficult and dangerous to store due to bulky and pressurised containers being required 
• Hydrogen forms an explosive mixture with air so could be hazardous