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An aqueous solution of sodium chloride, NaCl, is electrolysed using inert electrodes - OCR Gateway - GCSE Chemistry Combined Science - Question 3 - 2021 - Paper 10
Question 3
An aqueous solution of sodium chloride, NaCl, is electrolysed using inert electrodes. Which product is formed at the cathode? A. Chlorine B. Hydrogen C. Oxygen D. ... show full transcript
Worked Solution & Example Answer:An aqueous solution of sodium chloride, NaCl, is electrolysed using inert electrodes - OCR Gateway - GCSE Chemistry Combined Science - Question 3 - 2021 - Paper 10
Step 1
Which product is formed at the cathode?
Answer
During the electrolysis of sodium chloride (NaCl) solution, the products formed at the electrodes depend on the reactions occurring at the cathode and anode. The cathode is where reduction happens.
In an aqueous NaCl solution, the relevant ions present are Na⁺ and OH⁻ at the cathode. The Na⁺ ions are not reduced in this case because they are more stable as ions compared to the reduction of water molecules.
The reduction of water at the cathode can be represented by the equation:
Hence, hydrogen gas is produced at the cathode as a result of the electrolysis of aqueous NaCl.