Identification of ions and gases: past paper questions
Real questions on identification of ions and gases
The newest 20 of 113 written questions. Open one to see it on the real paper.
- 0971/32 · May/June 2026 · Q7b[2]
Sea water contains potassium ions. Name the test to identify potassium ions. Give the observations for a positive test.
See it on the paper → - 0971/42 · May/June 2026 · Q3e(i)[2]
(i) Name a lead(II) salt and a sulfate salt that will form lead(II) sulfate. lead (IT) Salt .......... .......... Sulfate Salt .......... .......... .......... .......... .......... ..........
See it on the paper → - 0971/32 · October/November 2025 · Q3a(iii)[2]
Describe a test to identify the presence of chloride ions, Cl – , in a sample of water. test observations
See it on the paper → - 0971/62 · October/November 2025 · Q1b(ii)[2]
After the filtration, the student washes the residue. Identify the two substances removed from the residue by washing. substance
See it on the paper → - 0971/62 · October/November 2025 · Q3a(ii)[1]
Identify the gas given off in (a)(i).
See it on the paper → - 0971/62 · October/November 2025 · Q3b[1]
To the second portion of solution E, the student adds about 1 cm 3 of dilute nitric acid followed by a few drops of aqueous barium nitrate. observations
See it on the paper → - 0971/62 · October/November 2025 · Q3c[1]
To the third portion of solution E, the student adds a few drops of acidified aqueous potassium manganate( VII ). observations Tests on solid F Table 3.1 shows the tests and the student’s observations for solid F. Table 3.1 tests observations test 1 yellow flame test 2 Dissolve the remaining solid F in distilled water...
See it on the paper → - 0971/62 · October/November 2025 · Q3d[3]
Identify the three ions in solid F.
See it on the paper → - 0971/31 · May/June 2025 · Q2b[1]
Potassium chloride is found in sea water and contains chloride ions. Describe a test for chloride ions. test observations
See it on the paper → - 0971/32 · May/June 2025 · Q1g[1]
a gas that is tested for using acidified aqueous potassium manganate( VII )
See it on the paper → - 0971/32 · May/June 2025 · Q2b[2]
Potassium bromide is found in sea water and contains bromide ions. Describe a test for bromide ions. test observations
See it on the paper → - 0971/32 · May/June 2025 · Q6b[1]
State the colour seen in the flame test for potassium ions. (b) In another experiment, a student adds potassium carbonate to dilute hydrochloric acid.
See it on the paper → - 0971/61 · May/June 2025 · Q3b(i)[1]
To the first portion of solution H, the student adds about 1 cm depth of dilute nitric acid followed by a few drops of aqueous barium nitrate. observations
See it on the paper → - 0971/61 · May/June 2025 · Q3b(ii)[1]
observations when added dropwise To the second portion of solution H, the student adds aqueous sodium hydroxide dropwise and then in excess.
See it on the paper → - 0971/61 · May/June 2025 · Q3b(iii)[1]
To the third portion of solution H, the student adds about 1 cm depth of dilute nitric acid followed by a few drops of aqueous silver nitrate. observations Tests on solid G Table 3.1 shows the tests and the student’s observations for solid G. Table 3.1 tests observations test 1 lilac coloured flame test 2 Dissolve the...
See it on the paper → - 0971/61 · May/June 2025 · Q3c[1]
Identify solid G.
See it on the paper → - 0971/62 · May/June 2025 · Q1e[1]
During the reaction a colourless liquid collects at the point marked X on Fig. 1.1. Suggest the identity of liquid X.
See it on the paper → - 0971/62 · May/June 2025 · Q1f[1]
The gas collected in A is not pure hydrogen. Suggest why the gas collected is not pure.
See it on the paper → - 0971/62 · May/June 2025 · Q3a[1]
To the first portion of solution J, the student adds aqueous sodium hydroxide dropwise and then in excess. observations when added dropwise
See it on the paper → - 0971/62 · May/June 2025 · Q3b[1]
To the second portion of solution J, the student adds 1 cm 3 of dilute nitric acid followed by a few drops of aqueous barium nitrate. observations
See it on the paper →
What examiners said
Only a quarter of the candidates could recall the test for chloride ions. A few suggested the test for chlorine gas but one in seven candidates made no attempt at this question.
— Examiner report, May/June 2025, 0971/31 Q2(b) (Cambridge)
The filtrate, solution H, was aqueous calcium chloride. The test carried out was the test for sulfate ions. As there are no sulfate ions in aqueous calcium chloride, there should have been no change. A common error was to state ‘white precipitate’; the expected result for a positive sulfate test.
— Examiner report, May/June 2025, 0971/61 Q3(b)(i) (Cambridge)
The expected observations on addition of aqueous sodium hydroxide was the formation of a white precipitate on dropwise addition, which then remained when excess aqueous sodium hydroxide was added. The vast majority of candidates performed well, however, some candidates gave the expected result for the addition of aqueous ammonia or thought that ammonia would be made (possibly confusing the test us...
— Examiner report, May/June 2025, 0971/61 Q3(b)(ii) (Cambridge)
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