Question

Can you explain why is bimolecular dehydran not appropriate for the preparation of ethyl methyl ether?

Answer 1

"Bimolecular dehydration" is a way of preparing diethyl ether from the dehydrating action of concentrated sulfuric acid on ethanol. The dehydrating agent, conc. H2SO4 abstracts a hydrogen from one ethanol and a hydroxyl (the -OH group) of a neighbor. Those radicals formed, join together. Sulfuric acid grabs a mole of water.
So this method works only with symmetrical ethers: di[alkyl] ethers. Methyl Ethyl ether is better prepared from Sodium ethoxide and methanol or Sodium methoxide and ethanol.