0654.C12.5.02 — Describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations: (a). ammonium, NH4+ (b). calcium, Ca2+ (c: past paper questions

Real questions on 0654.c12.5.02 — describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations: (a). ammonium, nh4+ (b). calcium, ca2+ (c

The newest 5 of 5 written questions. Open one to see it on the real paper.

1. 0654/41 · October/November 2025 · Q7a[3]

   A student tests three different solutions to identify the ion in each solution. test observation ion add aqueous sodium hydroxide cream precipitate SO 42– acidify with dilute nitric acid and then add aqueous silver nitrate blue precipitate Br – acidify with dilute nitric acid and then add aqueous barium nitrate white p...

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2. 0654/42 · October/November 2025 · Q7b(i)[1]

   State the colour of the precipitate.

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3. 0654/32 · February/March 2023 · Q11c[2]

   Describe the test used to identify iron( II ) ions and give the observation for a positive result. test observation

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4. 0654/43 · October/November 2022 · Q5b(i)[1]

   State the colour of the precipitate of iron( II ) hydroxide.

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5. 0654/32 · February/March 2022 · Q5b[2]

   Fig. 5.1 shows an aqueous solution of iron( III ) chloride. Fig. 5.1 A student tests the solution to confirm that the label is correct. State the test for aqueous iron( III ) ions (Fe 3+ ) and give the observation for a positive result. test observation

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What examiners said

Only a small percentage of candidates could recall that the precipitate of iron(II) hydroxide is green in colour. The most common incorrect response seen was orange/brown.

— Examiner report, October/November 2022, 0654/43 Q5(b)(i) (Cambridge)

No candidates knew the chemical test for aqueous iron(III) ions. Many candidates did not attempt this question.

— Examiner report, February/March 2022, 0654/32 Q5(b) (Cambridge)