Preliminary Tests for Anions # Qualitative Analysis of Inorganic Salts

Prepared by Vijay Kumar Sethi Qualitative analysis of inorganic salt involves the detection or identification of cation and anion present in a salt. Salts:- obtained by neutralization of an acid and a base. Positive part of the salt, cation, is contributed by a base Negative part of the salt, anion, is contributed by an acid. Cation: Basic radical; Anion: Acidic radical Analysis of Anions( Acidic radicals):- Classified in 3 Groups Dilute H2 SO4 group:- CO3^(2−), S^(2−), NO2^−, SO3^(2−), 〖CH3 COO〗^− Concentrated H2 SO4 group:- Cl^−, Br^−, I^−, NO3^−, C2 O4^(2−) Independent group:- SO4^(2−), PO4^(3−) Based on the fact that when salt treated with dilute or conc. Sulphuric acid , characteristic gas or vapour is produced by a particular anion , which can be identified then that anion is confirmed by confirmatory tests. These are Preliminary test. Salts containing SO4^(2−) and PO4^(3−) reacts neither with dil. H2 SO4 nor with conc. H2 SO4. Therefore , these are identified by individual tests.