Statement 1: $\mathrm{R}-\mathrm{Cl}\left(\text{or}\right)\mathrm{RBr}\stackrel{\mathrm{NaI}}{\to }\mathrm{R}-\mathrm{I}\left(\text{Finkelstein reaction}\right)$  acetone is the solvent used

Statement 2: NaCl (or) NaBr the byproducts are insoluble in dry acetone which facilitates the forward reaction

$R-X+NaI\stackrel{\text{Dry acetone}}{\to }R-I+NaX\left(-X=Cl,-Br\right)$

Ionic nature of NaCl > NaBr > NaI

NaCl and NaBr are insoluble in acetone. They can be removed easily

According to Lechatlier's principle removal of products favours forward reaction.