Question detail

Chemical changes case 143 redox-boundary. A student explains a redox change. Which option uses the safest chemistry wording? Focus on aluminium ions gaining electrons the cathode form aluminium in Using electrolysis to extract metals, not on a neighbouring Unit 4.4 reaction idea.

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. Chemical changes case 143 redox-boundary: Links oxidation or reduction to the correct electron or oxygen change for aluminium ions gaining electrons the cathode form aluminium
B. Chemical changes case 143 redox-boundary: Uses reduction and displacement as if they mean the same thing (Using electrolysis to extract metals)
C. Chemical changes case 143 redox-boundary: Calls the reaction redox without naming what changes (aluminium ions gaining electrons the cathode form aluminium)
D. Chemical changes case 143 redox-boundary: Confuses oxidation state with ionic charge in the answer (Electrolysis)

Answer

The correct option is Chemical changes case 143 redox-boundary: Links oxidation or reduction to the correct electron or oxygen change for aluminium ions gaining electrons the cathode form aluminium.

Explanation

The correct option is Chemical changes case 143 redox-boundary: Links oxidation or reduction to the correct electron or oxygen change for aluminium ions gaining electrons the cathode form aluminium. It is correct because it directly supports the approved learning objective to describe aluminium ions gaining electrons at the cathode to form aluminium in Using electrolysis to extract metals. The other options are incorrect because they blur a Unit 4.4 concept boundary: acid versus alkali versus base, oxidation versus reduction, displacement versus reduction, electrolysis versus electroplating, anode versus cathode, positive versus negative ions, oxidation state versus ionic charge, or strong acid versus concentrated acid.

Common mistake

Aluminium ions are reduced to aluminium metal at the anode

Students often think that aluminium ions gain electrons at the anode, so aluminium metal is produced there

Aluminium ions (Al³⁺) are reduced at the cathode, where they gain three electrons to form aluminium metal (Al). The anode is where oxidation occurs, so oxygen gas is produced from oxide ions.

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For Using electrolysis to extract metals, which electrolysis focus answer best supports this Unit 4.4 objective: Describe aluminium ions gaining electrons at the cathode to form aluminium?