Chapter summary
Qualitative Analysis, at a glance
Identify ions and gases using observations that distinguish them.
O-Level 6092 (2026) / SEC G3 K324 (2027)
Quick revision
Revisit the essentials, then return to an explanation when you need it.
For cations, record precipitate colour and behaviour in excess reagent. Use fresh portions. For chloride/sulfate tests acidify with nitric acid; do not introduce the ion being tested.
Pure only
Bubbles alone do not identify a gas. State the gas test and its positive observation. Iodide testing is an additional Pure requirement.
Check your understandingWhich reagent distinguishes Al3+ from Zn2+ after both dissolve in excess NaOH?Think it through, then reveal the answer
Aqueous ammonia on a fresh portion: aluminium hydroxide stays insoluble in excess; zinc hydroxide dissolves.