Question detail

For Electrolysis of aqueous solutions, which ion focus answer best supports this Unit 4.4 objective: Identify products of aqueous electrolysis using suitable chemical tests where appropriate?

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Electrolysis

Question

A. Hydrogen ions and hydroxide ions - correct ion focus for aqueous electrolysis
B. Wrong ion focus: confuses aqueous electrolysis with a nearby Unit 4.4 chemical change idea
C. Wrong particle check: uses the wrong ion, electrode, acid-base term, or product for Electrolysis of aqueous solutions
D. Wrong reaction link: does not support Identify products of aqueous electrolysis using suitable chemical tests where appropriate

Answer

The correct option is Hydrogen ions and hydroxide ions - correct ion focus for aqueous electrolysis.

Explanation

The correct option is Hydrogen ions and hydroxide ions - correct ion focus for aqueous electrolysis. Hydrogen ions and hydroxide ions - correct ion focus for aqueous electrolysis is correct because it directly supports the approved learning objective to identify products of aqueous electrolysis using suitable chemical tests where appropriate. This ion focus variant asks students to separate aqueous electrolysis from similar Unit 4.4 chemical-change ideas. The reasoning belongs to Electrolysis of aqueous solutions within Electrolysis, so it should not be confused with nearby ideas about acids, alkalis, bases, oxidation, reduction, displacement, reactivity, electrolysis, electrodes, ions, pH, or salt preparation unless those are named in the objective. Use the focus term aqueous electrolysis to keep the answer aligned with AQA GCSE Chemistry 8462 Unit 4.4 Chemical changes. Keep acid, alkali and base distinct; keep oxidation and reduction distinct; do not mix reduction with displacement; keep electrolysis separate from electroplating; distinguish anode from cathode, positive ions from negative ions, oxidation state from ionic charge, and strong acid from concentrated acid. The other options are weaker because they either use the wrong reaction type, wrong ion, wrong electrode, wrong acid-base distinction, vague wording, or the wrong chemical-change context.

Common mistake

Misidentifying the anode product

Students often think that oxygen is always produced at the anode in aqueous electrolysis, even when halide ions are present.

Explain that if halide ions (Cl⁻, Br⁻, I⁻) are present, the anode reaction will produce the corresponding halogen (Cl₂, Br₂, I₂) because the halide oxidation potential is lower than that of water. Use the reactivity series and ion potentials to predict the correct anode product, and remind students to test the gas with appropriate chemical tests (e.g., sodium hydroxide for chlorine, silver nitrate for bromine).

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