P3.10—Qualitative analysis notes and tests

Qualitative analysis identifies ions, gases or organic groups by a sequence of reagent additions and observations. Record precipitate colour, solubility in excess reagent, gas tests and organic-test outcomes precisely.

Follow the order in the notes and use excess reagent where specified. Effervescence suggests gas evolution; confirm the gas rather than treating bubbles as an identity proof.

A cation may form a coloured hydroxide precipitate that dissolves in excess aqueous ammonia; an aldehyde can reduce Tollens’ reagent while a ketone does not under the same test.

One colour is rarely unique evidence. A complete identification uses the observation plus the confirmatory step and conditions.