The compound $\mathrm{A}$ on treatment with $\mathrm{Na}$ gives $\mathrm{B}$, and with $\text{P}\text{C}{\text{l}}_5$ gives $\mathrm{C}$. $\mathrm{B} \mathrm{and} \mathrm{C}$ react together to give diethyl ether. $\mathrm{A}, \mathrm{B} \mathrm{and} \mathrm{C}$ are in the order

The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol. This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction.