MHTCET 16 May 2024 Shift 2 Paper

Concept:Tertiary alkyl halides undergo nucleophilic substitution through a carbocation intermediate by the $\mathrm{S_N1}$ mechanism.Explanation:Silver fluoride ($\mathrm{AgF}$) provides a fluoride ion ($\mathrm{F^-}$) and the silver ion ($\mathrm{Ag^+}$) helps ionise the carbon–bromine bond.tert-Butyl bromide, $(\mathrm{CH_3})_3\mathrm{C{-}Br}$, forms a stable tertiary carbocation, $(\mathrm{CH_3})_3\mathrm{C^+}$.The fluoride ion then attacks this carbocation to give the substitution product.The reaction is:$$(\mathrm{CH_3})_3\mathrm{C{-}Br} + \mathrm{AgF} \rightarrow (\mathrm{CH_3})_3\mathrm{C{-}F} + \mathrm{AgBr}$$The product is 2-fluoro-2-methylpropane, which is tert-butyl fluoride.No rearrangement occurs because the tertiary carbocation is already highly stable.Answer:The major product is 2-fluoro-2-methylpropane.Correct option: B. 2-Fluoro-2-methylpropane.