A complex compound of `Cu^(3+)` with molecular formula `CoCl_(x).yH_(2)O` gives a total of 3 ions on dissolving in water. To satisy both the primary and secondary valencies in the complex , the number of `Cl^(-)` ions required is :

Options

A. one
B. four
C. three
D. zero

Answer

A

Explanation

Since cobalt is present as `Co^(3+)` and the co-ordination number of cobalt is 6 , the molecular formula of the compound should be `COCl_3.yNH_3` . As the complex gives three ions in aqueous solution , its structural formula must be `[CoCl(NH_3)_5]Cl_2` .
`[CoCl(NH_3)_5]Cl` `ltimplies` `[CoCl(NH_3)_5]^(+)` + `Cl^(-)`
Thus, only one `Cl^(-)` ion satisfies both primary and secondary vlalencies .