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A molten mixture of equal parts aluminium fluoride, AlF₃, and sodium chloride, NaCl, undergoes electrolysis - VCE - SSCE Chemistry - Question 7 - 2019 - Paper 1
Question 7
A molten mixture of equal parts aluminium fluoride, AlF₃, and sodium chloride, NaCl, undergoes electrolysis. Which one of the following statements about this reactio... show full transcript
Worked Solution & Example Answer:A molten mixture of equal parts aluminium fluoride, AlF₃, and sodium chloride, NaCl, undergoes electrolysis - VCE - SSCE Chemistry - Question 7 - 2019 - Paper 1
Step 1
C. Aluminium metal will be produced at the cathode and chlorine gas will be produced at the anode.
Answer
In the electrolysis of a molten mixture of aluminium fluoride (AlF₃) and sodium chloride (NaCl), the process involves the discharge of ions at the cathode and anode.
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At the cathode: Aluminium ions (Al³⁺) are reduced to form aluminium metal (Al) because they have a higher reduction potential than sodium ions (Na⁺). This means that Al will be deposited at the cathode.
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At the anode: Chloride ions (Cl⁻) are oxidized to form chlorine gas (Cl₂). This is favored as the anode reaction will produce chlorine gas.
Thus, the correct statement is that aluminium metal is produced at the cathode and chlorine gas at the anode.