Common Misconceptions
Part of Electrolysis of Aqueous Solutions — GCSE Chemistry
This common misconceptions covers Common Misconceptions within Electrolysis of Aqueous Solutions for GCSE Chemistry. Revise Electrolysis of Aqueous Solutions in Electrolysis for GCSE Chemistry with 20 exam-style questions and 0 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 12 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 12
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20 questions
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0 flashcards
⚠️ Common Misconceptions
Misconception 1: "Only the dissolved compound's ions are present in solution"
This is one of the most common errors. Water itself partially ionises: H₂O ⇌ H⁺ + OH⁻. So ANY aqueous solution always contains H⁺ and OH⁻ ions in addition to those from the dissolved salt. This is why the products of aqueous electrolysis can differ from molten electrolysis — hydrogen or oxygen may form instead of the metal or non-metal from the original compound.
Misconception 2: "The more concentrated the solution, the less likely the halogen forms"
The opposite is true. In a dilute halide solution, the OH⁻ concentration is relatively higher, so oxygen may form preferentially at the anode. In a CONCENTRATED halide solution (like brine), Cl⁻ ions greatly outnumber OH⁻ ions, so chlorine is produced. Concentration matters for the anode product when a halide is present.
Misconception 3: "Sodium metal forms at the cathode when brine is electrolysed"
Sodium does NOT form — hydrogen gas forms instead. Because sodium is above hydrogen in the reactivity series, H⁺ ions are more easily reduced and are preferentially discharged. To obtain sodium metal directly, you would need to electrolyse MOLTEN sodium chloride (no water present), as in the Downs process.