Aqueous copper sulphate solution (blue in colour) gives:
(i). A green precipitate with aqueous potassium fluoride and
(ii). A bright green solution with aqueous potassium chloride. Explain these experimental results.

Explanation

Aqueous solution of copper sulphate which is blue in colour exists as `[Cu(H_(2)O))_(4)]SO_(4)` and gives `[Cu(H_(2)O))_(4)]^(2+)` in solution. It is a labile complex entity in which the ligands `H_(2)O` get easily replaced by `F^(-)` ions of KF and by `Cl^(-)` ions of KCl.
`[Cu(H_(2)O)_(4)]^(2+)+4F^(-)underset("tetrafluoriodocuprate")([CuF_(4)]^(2-)+4H_(2)O)`
`overset(("blue"))([Cu(H_(2)O)_(4)]^(+))+4CI^(-)rarr underset(("bright green solution"))underset("tetrachloridocuprate"(II))([CuCI_(4)]^(2-)+4H_(2)O)`