(i) Williamson ether synthesis.
(ii) Unsymmetrical ether.

(i) Williamson’s ether synthesis is the process of obtaining ethers by treating an alkyl halide with a suitable sodium alkoxide. The sodium alkoxide required for this procedure is made by reacting sodium with suitable alcohol. Alkyl halide should be the major reactant in this reaction. Alkenes are produced primarily by secondary and tertiary halides.

(ii) Unsymmetrical ethers are defined as ethers that have distinct alkyl or aryl groups linked to the oxygen atom. Ethyl methyl ether, methyl phenyl ether, 4-chlorophenyl-4-nitrophenyl ether, and so on.