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4. The method used to extract a metal from its ore depends on the position of the metal in the reactivity series - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2022 - Paper 1
Question 4
4. The method used to extract a metal from its ore depends on the position of the metal in the reactivity series. (a) Aluminium is extracted from its ore by electro... show full transcript
Worked Solution & Example Answer:4. The method used to extract a metal from its ore depends on the position of the metal in the reactivity series - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2022 - Paper 1
Step 1
Explain why this method is used to extract aluminium from its ore.
Answer
Aluminium is extracted from its ore using electrolysis because it is very reactive, sitting high in the reactivity series. This means that aluminium cannot be easily reduced using carbon, as more reactive metals cannot be displaced by less reactive ones. The process of electrolysis provides the necessary energy to break down aluminium oxide (Al₂O₃) and obtain pure aluminium metal. During electrolysis, the ore is dissolved in molten cryolite to lower the melting point and then subjected to a strong electric current, which facilitates the extraction.
Step 2
Explain why this displacement reaction can be described as a redox reaction.
Answer
The displacement reaction between TiCl₄ and magnesium can be classified as a redox (reduction-oxidation) reaction because it involves the transfer of electrons. In this reaction, magnesium (Mg) acts as the reducing agent; it loses electrons and is oxidized from Mg to Mg²⁺. Meanwhile, titanium ions (Ti⁴⁺) accept these electrons and get reduced to form titanium (Ti). This exchange signifies that magnesium undergoes oxidation (loss of electrons), and titanium undergoes reduction (gain of electrons), fulfilling the criteria for a redox reaction.