Zusammenfassung der Ressource
Testing for ions
- Ammonium ions can be tested for by
adding a few drops of dilute sodium
hydroxide solution and heating.
- If ammonium ions are present, ammonia
gas will be a product of the reaction and
will turn red litmus paper blue.
- Carbonate ions can be
tested for by adding some
dilute hydrochloric acid.
- If carbonate ions are present, carbon
dioxide gas will be a product of the
reaction and will turn limewater cloudy.
- Sulphate ions can be tested
by firstly adding some dilute
hydrochloric acid followed by
some barium chloride
solution.
- If sulphate ions are present, barium
sulphate will be a product of the reaction
and a white precipitate will form.
- Halide ions
- Halide ions can be tested for by adding
some dilute nitric acid followed by
some silver nitrate solution
- Different halides form different
coloured precipitates as
different products are formed.
- Chlorine ions
- Silver chloride
- White precipitate
- Bromide ions
- Silver bromide
- Cream precipitate
- Iodide ions
- Silver iodide
- Yellow precipitate
- Nitrate ions
- Nitrate ions can be tested for by adding some
sodium hydroxide solution followed by some
aluminium powder or foil and then heating strongly.
- If nitrate ions are present, ammonia
gas will be a product of the reaction
and will turn red litmus paper blue
because it is a strong alkali.