Finkelstein Reaction (Halogen Exchange)

$$\text{R--Cl} / \text{R--Br} + \text{NaI} \xrightarrow{\text{Dry Acetone}} \text{R--I} + \text{NaCl} \downarrow / \text{NaBr} \downarrow$$

Concept: Alkyl chlorides or bromides are converted to alkyl iodides by treatment with sodium iodide ($$\text{NaI}$$) in dry acetone.

According to Le Chatelier’s principle, the reaction is driven forward because $$\text{NaCl}$$ and $$\text{NaBr}$$ are insoluble in dry acetone and precipitate out of solution.