Identification of Anions
Exam code: 5070
Identification of Anionsvideo
Identification of Anions

The acidification with aqueous silver nitrate and aqueous barium nitrate / chloride is done to remove ions that might give a false positive result
The most common ion that is removed is the carbonate ion
The choice of acid has to be considered so that it does not influence the results
For example, aqueous silver nitrate solution should not be acidified with hydrochloric acid as this will form a white precipitate due to the chloride ion in the acid
For example, aqueous barium nitrate / chloride solution should not be acidified with sulfuric acid as this will form a white precipitate due to the sulfate ion in the acid