0654.C4.1.08 — Construct ionic half-equations for reactions at the cathode (showing gain of electrons as a reduction reaction): past paper questions
Real questions on 0654.c4.1.08 — construct ionic half-equations for reactions at the cathode (showing gain of electrons as a reduction reaction)
The newest 9 of 9 written questions. Open one to see it on the real paper.
- 0973/41 · October/November 2024 · Q11c[2]
Construct the ionic half‑equation for the reaction at the cathode.
See it on the paper → - 0973/41 · October/November 2023 · Q11b[2]
Aqueous copper(II) sulfate can be electrolysed using carbon electrodes. Copper is formed at the cathode. Construct the ionic half-equation for the formation of copper.
See it on the paper → - 0973/42 · May/June 2023 · Q11c[2]
Copper is formed at the cathode in the electrolysis of aqueous copper chloride. Construct the ionic half‑equation for the formation of copper at the cathode.
See it on the paper → - 0973/41 · October/November 2022 · Q11c[2]
Copper atoms are formed from copper ions, Cu 2+ , at the cathode. Construct the balanced ionic half-equation for this reaction. Use the symbol e – for an electron.
See it on the paper → - 0973/42 · May/June 2022 · Q5b(ii)[1]
Write a balanced ionic half equation to show how a sodium atom forms a sodium ion. Use e – to represent an electron.
See it on the paper → - 0973/42 · May/June 2022 · Q5d(ii)[2]
Sodium chloride, NaCl, is an ionic compound. Draw a dot‑and‑cross diagram to show the bonding in sodium chloride. Include the charges on the ions.
See it on the paper → - 0973/41 · May/June 2021 · Q8b(ii)[2]
At the negative electrode copper ions, Cu 2+ , gain electrons to form copper metal, Cu. Construct the ionic half‑equation for the formation of copper at the negative electrode. Use e – to represent an electron.
See it on the paper → - 0973/41 · October/November 2020 · Q11b[2]
Molten sodium chloride can also be electrolysed. Sodium is made at the cathode. Write the balanced ionic half‑equation for the reaction at the cathode. Include state symbols.
See it on the paper → - 0973/41 · May/June 2019 · Q2b(iv)[2]
Write the ionic half-equation for the reaction occurring at the cathode during this electrolysis.
See it on the paper →
What examiners said
Many candidates did not attempt to construct the ionic half-equation for the formation of copper. Candidates that attempted to construct the ionic half-equation usually did not give the correct notation for the two electrons as 2e– or tried to include CuSO4 or C in their answer.
— Examiner report, October/November 2023, 0973/41 Q11(b) (Cambridge)
The half-equation was generally done well. Occasionally candidates got this the wrong way round showing the production of copper ions. A minority of candidates gave the charge of electrons as positive.
— Examiner report, May/June 2023, 0973/42 Q11(c) (Cambridge)
The ionic half-equation for the formation of copper was quite well known.
— Examiner report, May/June 2021, 0973/41 Q8(b)(ii) (Cambridge)
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