Titanium is a metal used in aircraft engines and medical implants. It is found in the Earth's crust as titanium dioxide (TiO₂), which must be converted into titanium metal through a series of steps involving chlorine gas and sodium or magnesium. Explain why titanium is more expensive to produce than iron, which is extracted using carbon in a blast furnace.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Titanium is highly valued for its strength and resistance to corrosion, yet its high production cost limits its widespread use compared to iron.
Model answer (5 marks)
1. Titanium cannot be reduced by carbon because it is more reactive than carbon, so carbon reduction would not work.
2. A more reactive metal such as sodium or magnesium must be used to displace titanium from its compounds.
3. Sodium and magnesium are themselves expensive to produce, adding cost to the process.
4. The reduction steps must be carried out in an inert atmosphere or under vacuum to avoid oxidation and contamination.
5. In contrast, iron can be extracted by carbon reduction in a blast furnace, which uses cheap coke and is a continuous, large‑scale operation, making iron cheaper to produce.
2. A more reactive metal such as sodium or magnesium must be used to displace titanium from its compounds.
3. Sodium and magnesium are themselves expensive to produce, adding cost to the process.
4. The reduction steps must be carried out in an inert atmosphere or under vacuum to avoid oxidation and contamination.
5. In contrast, iron can be extracted by carbon reduction in a blast furnace, which uses cheap coke and is a continuous, large‑scale operation, making iron cheaper to produce.
Examiner tips
- Use the exact terminology: ‘more reactive’, ‘displace’, ‘inert atmosphere’, ‘blast furnace’.
- Show the logical sequence: reactivity → need for sodium/magnesium → cost of these metals → need for inert conditions → comparison with iron’s cheap carbon reduction.
Common mistakes
- Saying titanium can be reduced by carbon; ignoring its higher reactivity.
- Forgetting that sodium/magnesium are expensive or that the process requires an inert atmosphere.
- Mixing up the reasons for iron’s lower cost with unrelated factors such as energy consumption.
Mark scheme (5 marks)
- Titanium cannot be extracted using carbon / carbon reduction because titanium is more reactive than carbon
- A more reactive metal (sodium or magnesium) is needed to displace/reduce titanium
- Sodium and magnesium are themselves expensive / costly metals to produce
- The process must be carried out in the absence of air / in an inert atmosphere to prevent oxidation / contamination
- Iron can be extracted using carbon/coke which is cheap and readily available, making its extraction cheaper / the blast furnace is a continuous / large-scale process
Related
- All OCR A-Level Chemistry B: Salters (H433) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
More Developing metals questions
- Aluminium is one of the most widely used metals in the world, found in products …
- Gold has been used by humans for thousands of years and is found as the native m…
- Iron is extracted from iron ore in a blast furnace. However, pure iron is rarely…
- Copper is an important metal used in electrical wiring. Most copper is extracted…