i) Li+,
Na+,
K+,
Ca2+
using
flame tests
- Lithum: red
- Sodium: orange (so strong can mask other colours)
- Potassium: lilac
- Calcium: brick red
ii) NH4+,
using sodium hydroxide solution and identifying the ammonia evolved
- NH4 + OH > NH3 + H2O
- ammonium ions + hydroxide ions > ammonia + water
- ammonia (pungent smelling gas) turns red litmus paper blue
iii) Cu2+,
Fe2+
and
Fe3+,
using sodium hydroxide solution
- Copper(ii) sulphate + sodium hydroxide > blue precipitate
- Iron(ii) sulphate + sodium hydroxide > green precipitate
- Iron(iii) sulphate + sodium hydroxide > brown precipitate
For the ammonia detecting the red litmus has to be damp btw.
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