0653.C12.4.02 — 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 0653.c12.4.02 — describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations: (a). ammonium, nh4+ (b). calcium, ca2+ (c
The newest 6 of 6 written questions. Open one to see it on the real paper.
- 0653/31 · May/June 2025 · Q5a[2]
A solid compound contains potassium ions. Describe the use of a flame test to identify potassium ions.
See it on the paper → - 0653/61 · May/June 2025 · Q3b(iii)[1]
State the name of the gas produced in the test with copper( II ) carbonate.
See it on the paper → - 0653/63 · May/June 2024 · Q3d(ii)[1]
Explain how the observations in Table 3.1 show that the green liquid contains sulfate ions.
See it on the paper → - 0653/63 · October/November 2023 · Q3c(ii)[1]
Tick (3) the name of the cation (positive ion) present in H. ammonium calcium copper zinc
See it on the paper → - 0653/62 · May/June 2023 · Q3b(iii)[1]
The student adds aqueous sodium hydroxide to the colourless solution. A white precipitate forms which is soluble in excess aqueous sodium hydroxide. Tick (3) the name of the cation present in the colourless solution. ammonium calcium copper( II ) iron( III ) zinc
See it on the paper → - 0653/12 · October/November 2022 · Q21[1]
Which pair of gases can be identified using damp litmus paper and limewater?
See it on the paper →
What examiners said
It was clear that candidates were unfamiliar with the method of doing a flame test. A few candidates stated to use a splint but hardly any mentioned to burn the compound in the blue flame of the Bunsen burner. Credit was given to the candidates who knew that potassium gives a lilac colour in the flame test.
— Examiner report, May/June 2025, 0653/31 Q5(a) (Cambridge)
Most candidates identified that the gas produced was carbon dioxide. A relatively common incorrect answer was hydrogen.
— Examiner report, May/June 2025, 0653/61 Q3(b)(iii) (Cambridge)
Many candidates correctly identified zinc. It was common to see more than one box ticked.
— Examiner report, May/June 2023, 0653/62 Q3(b)(iii) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.