Question

How will you prepare n propyl iodide from n-propyl bromide?

Answer 1

n-propyl bromide on heating with a concentrated solution of sodium iodide in dry acetone gives n-propyl iodide. This S_N² reaction is called Finkelstein reaction.

\[\ce{\underset{\text{n – propyl iodide }}{CH3 - CH2 - CH2Br} + NaI ->[Acetone] \underset{\text{n-propyl iodide}}{CH3 - CH2 - CH2}I + NaBr}\]