Free resource · O-Level and SEC (G3)
O-Level Chemistry QA Notes (6092): Free PDF
The Notes for Qualitative Analysis are printed in Paper 3, the practical paper, of O-Level Chemistry 6092 and SEC G3 Chemistry K324. They list tests for five anions, the effects of aqueous sodium hydroxide and aqueous ammonia on seven cations, and tests for six gases. Ions not in the notes can still be tested, but then you are only asked to draw conclusions of a general nature.
Test for anions
Printed exactly as in the O-Level Chemistry paper. ppt. means precipitate.
| anion | test | test result |
|---|---|---|
| carbonate (CO₃²⁻) | add dilute acid | effervescence, carbon dioxide produced |
| chloride (Cl⁻) [in solution] | acidify with dilute nitric acid, then add aqueous silver nitrate | white ppt. |
| iodide (I⁻) [in solution] | acidify with dilute nitric acid, then add aqueous silver nitrate | yellow ppt. |
| nitrate (NO₃⁻) [in solution] | add aqueous sodium hydroxide, then aluminium foil; warm carefully | ammonia produced |
| sulfate (SO₄²⁻) [in solution] | acidify with dilute nitric acid, then add aqueous barium nitrate | white ppt. |
Test for aqueous cations
| cation | effect of aqueous sodium hydroxide | effect of aqueous ammonia |
|---|---|---|
| aluminium (Al³⁺) | white ppt., soluble in excess giving a colourless solution | white ppt., insoluble in excess |
| ammonium (NH₄⁺) | ammonia produced on warming | – |
| calcium (Ca²⁺) | white ppt., insoluble in excess | no ppt. |
| copper(II) (Cu²⁺) | light blue ppt., insoluble in excess | light blue ppt., soluble in excess giving a dark blue solution |
| iron(II) (Fe²⁺) | green ppt., insoluble in excess | green ppt., insoluble in excess |
| iron(III) (Fe³⁺) | red-brown ppt., insoluble in excess | red-brown ppt., insoluble in excess |
| zinc (Zn²⁺) | white ppt., soluble in excess giving a colourless solution | white ppt., soluble in excess giving a colourless solution |
Test for gases
| gas | test and test result |
|---|---|
| ammonia (NH₃) | turns damp red litmus paper blue |
| carbon dioxide (CO₂) | gives white ppt. with limewater (ppt. dissolves with excess CO₂) |
| chlorine (Cl₂) | bleaches damp litmus paper |
| hydrogen (H₂) | ‘pops’ with a lighted splint |
| oxygen (O₂) | relights a glowing splint |
| sulfur dioxide (SO₂) | turns aqueous acidified potassium manganate(VII) from purple to colourless |
Questions students ask
Are the QA notes given in the O-Level Chemistry exam?
Yes, but only in Paper 3, the practical paper. The syllabus says a copy of the Notes for Qualitative Analysis will be printed as part of that paper. Papers 1 and 2 come with the Periodic Table only, so for theory questions on ion and gas tests you need to know the results yourself.
What if an ion is not in the QA notes?
The syllabus says reactions involving ions not in the notes may still be tested. In that case you will not be expected to identify the ion, only to draw conclusions of a general nature from what you observe.
Do I need to test for sulfur dioxide in the practical?
The syllabus says candidates would not be required to carry out tests involving sulfur dioxide gas. The test for sulfur dioxide is still listed in the notes, using aqueous acidified potassium manganate(VII).
Are the SEC G3 Chemistry QA notes the same as the O-Level ones?
Yes. The Notes for Qualitative Analysis page in the 2027 SEC G3 Chemistry syllabus (K324) matches the 2026 O-Level Chemistry syllabus (6092) word for word, with the same anion, cation and gas tables.
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Source
- SEAB, O-Level Chemistry syllabus 6092 (2026), Notes for Qualitative Analysis
- SEAB, SEC G3 Chemistry syllabus K324 (2027)
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