MHTCET 15 Apr 2026 Shift 2 Paper

Concept:The conversion of alkyl bromides to alkyl fluorides using a metallic fluoride like $\mathrm{Hg}_{2}\mathrm{~F}_{2}$ is called the Swarts reaction.Explanation:The given reaction is:$$2 \mathrm{R}-\mathrm{Br} + \mathrm{Hg}_{2}\mathrm{~F}_{2} \rightarrow 2 \mathrm{R}-\mathrm{F} + \mathrm{Hg}_{2}\mathrm{Br}_{2}$$In this reaction, the bromine atom in $\mathrm{R}-\mathrm{Br}$ is exchanged with fluorine.The fluorine donor is mercurous fluoride, $\mathrm{Hg}_{2}\mathrm{~F}_{2}$, which is an inorganic metallic fluoride.This is a halogen exchange method used specifically to prepare alkyl fluorides.Alkyl fluorides are difficult to prepare directly, so this exchange reaction is very useful.The method is named after its discoverer and is commonly known as the Swarts reaction or Swartz reaction.It is different from the Finkelstein reaction, which uses $\mathrm{NaI}$ to prepare alkyl iodides.Hence, the correct option is B.Answer:Option B: Swartz reaction (also written as Swarts reaction).