Question

(s)-2-iodopentane undergoes racemization in a solution of sodium iodide in dmso. explain

Please explain (s)-2-iodopentane's role in this and why I- is present

Answer 1

RACEMIZARTION: When by means of any chemical change or in general there are equal amount of two isomers ( R and S) present in a solution, the solution is called racemic mixture and the process of formation of racemic mioxture is known as racemization.

In the above reaction namely substitution, the solvent used is DMSO i.e, dimethylsulphosoxide which is a polar aprotic solvent and promotes the S_N¹ (substitution unoimolecular) by forming a stable planar carbocation intermediate. A nd in next step the iodide ionn can attack from above the oplane as well as from bellow the plane forming the (S) and (R) isomers respectively. That is a racemic mixture is obtained and this substitution is a process opf racemization.