The reaction $\mathrm{R}-\mathrm{ONa}+\mathrm{R}{}^{\prime }-\mathrm{X}\to \mathrm{R}-\mathrm{O}-\mathrm{R}{}^{\prime }+\mathrm{NaX}$ can be classified as:

Solution & Explanation

\textbf{Answer:} (A) Williamson ether synthesis reaction \textbf{Solution:} An alkoxide (or aryloxide) ion reacting with an alkyl halide to form an ether is the Williamson ether synthesis: $\mathrm{R}-\mathrm{ONa}+\mathrm{R}{}^{\prime }-\mathrm{X}\to \mathrm{R}-\mathrm{O}-\mathrm{R}{}^{\prime }+\mathrm{NaX}$ The reaction proceeds by an $S_{N}2$ attack of the alkoxide on the alkyl halide. It produces an ether (not an alcohol), so it is the Williamson \emph{ether} synthesis.