Which is the major product from the following consecutive reactions?

Question

Quizplus · Accepted Answer

The first reaction is a substitution of an alcohol with thionyl chloride (SOCl2), which forms the corresponding alkyl chloride (I). This product can then undergo an SN2 (substitution nucleophilic bimolecular) reaction with sodium iodide (NaI) in acetone to form the alkyl iodide (III) as the major product. The other products (II and IV) are minor products and come from competing reaction pathways, such as elimination (II) and substitution with the solvent (IV).

Which Is the Major Product from the Following Consecutive Reactions