Question

`AIF_(3)` is insoluble in anhydrous `HF` but when little `KF` is added to the compound it becomes soluble On addition of `BF_(3),AIF_(3)` precipitated Write the balanced chemical equations .

Answer 1

`AIF_(3)` does not dissolve in anhydrous HF because it is not available for co-ordination with `AIF_(3)` due to the presence of intermolecular hydrogen bonding it dissolves in KF becaue `F^(-)` ion can co-ordinate with `AIF_(3)` and a salt is formed
`3KF+AIF_(3)rarrK_(3)[AIF_(6)]`
The salt is decomposed by `BF_(3)` which is Lewis acid (electron deficient) and `AIF_(3)` is precipitated
`K_(3)(AIF_(6))+3BF_(3)rarrAIF_(3)+3KBF_(4)`