(b) Finkelstein reaction is an SN2 reaction that involves the exchange of one halogen by iodine, In this reaction, alkyl chloride/bromides are treated with sodium iodide in acetone to form alkyl iodide and NaCl∕NaBr. Acetone is used because NaCl∕NaBr are less soluble in acetone hence, they can precipitate out. R−Cl+NaI‌