JEE Main · 2025 · 23 Jan 2025 · Shift 1 · Haloalkanes and Haloarenes

Each named halogenation/coupling reaction gives a characteristic product:

Swarts reaction replaces $\mathrm{Cl}$/$\mathrm{Br}$ with $\mathrm{F}$ using a metal fluoride: $\mathrm{Et}-\mathrm{Cl}\stackrel{KF/DMF}{\to }\mathrm{Et}-\mathrm{F}$.

Sandmeyer's reaction converts an arenediazonium salt to an aryl halide or nitrile using $\mathrm{Cu}(\mathrm{I})$ salts: $\mathrm{Ph}{\mathrm{N}}_2^{+}\mathrm{C}{\mathrm{l}}^{-}\stackrel{CuCN/KCN}{\to }\mathrm{PhCN}$.

Wurtz–Fittig reaction couples an aryl halide with an alkyl halide using sodium in dry ether, the major coupled product being the alkylarene: $\mathrm{Ph}-\mathrm{Cl}+\mathrm{Et}-\mathrm{Cl}\stackrel{\mathrm{Na},\mathrm{ether}}{\to }\mathrm{Ph}-\mathrm{Et}$.

Finkelstein reaction converts an alkyl chloride/bromide to the corresponding iodide using $\mathrm{NaI}$ in acetone: $\mathrm{Et}-\mathrm{Cl}\stackrel{NaI/acetone}{\to }\mathrm{Et}-\mathrm{I}$.

The correct pairing is Swarts–Ethyl fluoride, Sandmeyer's–Cyanobenzene, Wurtz–Fittig–Ethyl benzene, Finkelstein–Ethyl iodide.