qualitative analysis of ions on a test-tube scale; processes and techniques needed to identify the following ions in an unknown compound:
(i) anions:
- CO32–, by reaction with H+(aq) forming CO2(g) (see 2.1.4c)
- SO42–, by precipitation with Ba2+(aq)
- Cl–, Br–, I– (see 3.1.3g)
(ii) cations: NH4+, by reaction with warm NaOH(aq) forming NH3.
Sequence of tests required is carbonate, sulfate then halide. (BaCO3 and Ag2SO4 are both insoluble.) PAG4