Question

`AlF_(3)` is insoluble in anhydrous `HF` but dissolves on addition of `NaF. AlF_(3)` precipitates out of the resulting solution when gaseous `BF_(3)` is bubbled through. Give reasons.

Answer 1

Aluminium trifuoride `(AIF_(3))` is insoluble in anhydrous HF because of its covalent nature. However, it forms a complex compound on reacting with `NaF` which bond polarities cancel out.