Ethers Knowledge-Based Download PDF

Questions

1. 1.

   Why are anhydrous ethers, such as diethyl ether and tetrahydrofuran, widely used as solvents for the preparation and reactions of Grignard reagents?

   • A) They serve as Brønsted-Lowry acids that donate protons to stabilize the carbanion intermediate.
   • B) The lone pairs of electrons on the ethereal oxygen atom act as Lewis bases to coordinate with and stabilize the magnesium center.
   • C) They irreversibly oxidize magnesium metal to generate high concentrations of soluble organomagnesium radical cations.
   • D) Their alkyl chains form an impenetrable hydrophobic barrier that suppresses all polar interactions within the reaction mixture.
2. 2.

   Which major organic product is formed when 2-methyloxirane is treated with sodium methoxide in methanol?

   • A) 1-methoxypropan-2-ol
   • B) 2-methoxypropan-1-ol
   • C) 1,2-dimethoxypropane
   • D) 2-methoxypropene
3. 3.

   What are the major organic products formed when methoxybenzene (anisole) is heated with an excess of concentrated hydroiodic acid ($\text{HI}$)?

   • A) Iodobenzene and methanol
   • B) Iodobenzene and iodomethane
   • C) Phenol and methanol
   • D) Phenol and iodomethane
4. 4.

   Which combination of reagents is most suitable for preparing tert-butyl methyl ether in high yield via the Williamson ether synthesis?

   • A) Sodium tert-butoxide and bromomethane
   • B) Sodium methoxide and 2-bromo-2-methylpropane
   • C) Methanol and 2-methylpropan-2-ol with concentrated sulfuric acid
   • D) Sodium tert-butoxide and 2-bromopropane
5. 5.

   Which of the following statements correctly compares the boiling points and intermolecular forces of diethyl ether and 1-butanol, which are constitutional isomers?

   • A) Diethyl ether has a higher boiling point because it forms extensive intermolecular hydrogen bonds between its molecules.
   • B) Both compounds have approximately equal boiling points because constitutional isomers share identical intermolecular forces.
   • C) 1-Butanol has a higher boiling point because it exhibits intermolecular hydrogen bonding, which is absent between diethyl ether molecules.
   • D) Diethyl ether has a higher boiling point because its central oxygen atom creates significantly stronger dipole-dipole interactions than a hydroxyl group.