Co-ordiantion compounds show structural isomerism and it is different from the nature of the isomerism which we generally come across in organic compounds. The co-ordination and linkage isomers depending upon their upon the number of ions which they furnish upon dissociation in aqueous solution . The isomers belonging to a particular type can also be distinguished from each structural isomerism, the co-ordination compounds are also involved in geometrical and optical isomerism. Whereas optical octahedral and square planar complexes can exhibit geometrical isomerism.
1 . Aqueous solutions of `` on addition of excess of concentrated HCl turns blue due to the formation of

Options

A. `[Co(H_(2)O)_(4)Cl_(2)]`
B. `[Co(H_(2)O)_(4)Cl_(4)]^(2-)`
C. `[CoCl_(4)]^(2-)`
D. `[Co(H_(2)O)_(2)Cl_(2)]`

Answer

c

Explanation

`CoCl_2` is a weak Lewis acid and takes up two `Cl^(-)` ions to form a salt `[CoCl_4]^(2-)` which is tetrahedral . In the anhydrous state, `CoCl_2` is violet and in solution the tetrahedral salt formed on reacting with HCl is blue in colour.