# Why is Finkelstein reaction not conducted using NaF?

I was studying the Finkelstein reaction and all sources through which I have studied this reaction indicate that the reaction uses $$\ce{NaI},$$ where $$\ce{I-}$$ acts as the nucleophile which will then replace $$\ce{X}$$ from the alkyl halide $$\ce{R-X}.$$

This is an $$\mathrm{S_N2}$$ reaction, hence we use a polar aprotic solvent (PAS, usually acetone) as PAS stabilizes the $$\ce{Na+}$$ cation. We know that while using a PAS the order of nucleophilicity is

$$\ce{F-} > \ce{Cl-} > \ce{Br-} > \ce{I-}.$$

The part I am struggling with is that even though $$\ce{F-}$$ is a better nucleophile than $$\ce{I-}$$ in a PAS, why do we still use $$\ce{NaF}$$ rather than $$\ce{NaI}?$$

• Search for the solubility of NaF in acetone. – Waylander May 19 '20 at 20:34