Metals below carbon in the reactivity series
2 marks · HardExplain why extraction of iron using carbon is more economical than extraction using electrolysis. Give two reasons.
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It is more economical because using carbon requires less energy than electrolysis and carbon is a cheaper reducing agent than electricity.
Also accept: Less energy is needed for carbon reduction than for electrolysis, and carbon is less expensive than the electricity required for electrolysis.
Common mistakes: Saying only that carbon is cheaper, without mentioning energy.; Saying carbon is quicker (this is not an economic reason).
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Marking points
B1 · 1 mark · States that using carbon requires less energy than electrolysis (or electrolysis uses more energy).
B2 · 1 mark · States that carbon is a cheaper reducing agent than electricity.
Worked solution
Extraction using carbon is more economical because:
- It needs less energy compared to electrolysis.
- Carbon is less expensive than the electricity used in electrolysis.