Explanation:
The potassium fluoride will dissociate into potassium ions and fluoride ions in their aqueous solution.
[tex]KF(aq)\rightarrow K^+(aq)+F^-(aq)[/tex]
So, when 1 mol of  hexaaqua aluminium (III) reacts with 6 moles of fluoride ion it gives 1 mole of hexafluoroaluminate(III).
The reaction is given as:
[tex]Al(H_2O)_6^{3+}(aq)+6F^-(aq)\rightleftharpoons AlF_6^{3-}(aq)+6H_2O(l)[/tex]