PREVIOUSLY ASKED IN:
West Bengal Civil Service (WBCS) Preliminary 2023
Answer
Aluminium metal
Explanation
In the thermit process, aluminium powder is used to reduce iron oxide. The molten iron produced in this reaction helps weld or repair cracks in railway tracks.
Key Points
- Aluminium acts as a reducing agent due to its high affinity for oxygen.
- It is a highly exothermic reaction.
- The reaction formula is: Fe2O3 + 2Al → Al2O3 + 2Fe + heat.
Additional Information
- The heat generated is enough to melt iron (about 2500°C).
- It is an old and effective welding method that doesn't require an external power source.