In qualitative analysis, on what basis cations are grouped ?
Answers
Classical qualitative inorganic analysis is a method of analytical chemistry to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution. The solution is treated with reagents to test for reactions characteristic of certain ions, which may cause color change, solid forming, and other visible changes.
Cations are divided into six groups. Each group has a common reagent that can be used to separate them from the solution. Because cationic analysis is based on the solubility products of the ions, meaningful results can be obtained only if separation is performed in a specified sequence. This is due to the fact that some ions of one group may also react with the reagent of another group. For example, both Ba2+ and Sr2+ will react with the SO42- ion to form a solid. Hence, mathematical calculations should be done before choosing the SO42- ion for selective precipitation in a solution that may contain both Ba2+ and Sr2+.
Qualitative Analysis: It is a method to find the elemental decomposition of inorganic compounds, mainly focusing on detecting ions in an aqueous solution.
Cations are detected based on their properties of elements are classified into six groups.
1st analytical group of cations: It includes of ions which form insoluble chlorides.
2nd analytical group of cations: It includes of ions which form acid-insoluble sulphides.
3rd analytical group of cations: It consists of ions that form base-insoluble sulphides and hydroxides.
4th analytical group of cations: It consist of ions which form insoluble phosphates.
5th analytical group of cations: It consists of alkali metal ions and ammonium ion.