Metals above carbon in the reactivity series
3 marks · NormalTitanium cannot be extracted from its oxide using carbon. It is often extracted by heating titanium oxide with sodium or magnesium.
Explain why this method is expensive and give a reason why this process is used instead of reduction with carbon.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Also accept: This method is expensive because magnesium or sodium is themselves expensive to produce, as they are extracted by electrolysis. This process is used because carbon cannot reduce titanium oxide as titanium is more reactive than carbon.; Expensive due to the cost of obtaining sodium/magnesium; carbon is not reactive enough to reduce titanium oxide.
Common mistakes: Not mentioning why carbon cannot be used
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Identifies that the process is expensive because the more reactive metal is costly to obtain/use.
B2 · 1 mark · Recognises that the more reactive metal has to be produced by expensive processes (e.g. electrolysis).
B3 · 1 mark · States the process is used because carbon cannot reduce titanium oxide (because Ti is more reactive than carbon).
Worked solution
This extraction method is expensive because magnesium or sodium is themselves expensive to produce, usually by electrolysis. This process is used instead of carbon because titanium is more reactive than carbon, so carbon cannot reduce titanium oxide.