How coordination compounds are used in analytical chemistry ?

Explanation

(i) Multidentate ligand, EDTA. forms highly stable complexes with metal ions like `Ca^(2+)` and `Mg^(2+)`. This is used to estimate the hardness of water by a simple titration method using EDTA -solution. A confirmatory test for the detection of copper (II) involves the formation of a deep-blue coloured complex, `[Cu(NH_3)_4]^(2+)` , on addition of ammonia, solution to a solution of copper (II) salt.`Cu^(2+)+4NH_3rarr[Cu(NH_3)_4]^(2+)` Tetra - ammine copper (n) ion.