Ethers Knowledge-Based Practice

Questions

1. 1.

   When aliphatic ethers such as diethyl ether and diisopropyl ether are exposed to atmospheric oxygen and light over extended periods, they slowly undergo autooxidation. Which of the following classes of hazardous, shock-sensitive compounds is primarily formed through this process?

   • A) Organic peroxides and hydroperoxides
   • B) Carboxylic acids and aldehydes
   • C) Esters and acid anhydrides
   • D) Epoxides and vicinal diols
2. 2.

   Why are ethers such as diethyl ether and tetrahydrofuran (THF) commonly used as solvents in the preparation and handling of Grignard reagents?

   • A) They act as protic solvents that facilitate the reaction by donating acidic protons to the alkyl halide.
   • B) Their oxygen lone pairs act as Lewis bases that coordinate to and stabilize the electron-deficient magnesium atom.
   • C) They act as strong oxidizing agents that convert elemental magnesium into reactive magnesium cations.
   • D) They form irreversible covalent carbon-oxygen bonds with the carbanion to prevent spontaneous dimerization.
3. 3.

   When methoxybenzene (anisole) is heated with an excess of concentrated hydroiodic acid ($\text{HI}$), which of the following pairs of organic products is formed?

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

   Which of the following combinations of reactants is most suitable for preparing tert-butyl ethyl ether via the Williamson ether synthesis?

   • A) Sodium ethoxide and 2-bromo-2-methylpropane
   • B) Ethanol and 2-methylpropan-2-ol in the presence of dilute sulfuric acid
   • C) Potassium tert-butoxide and bromoethane
   • D) 2-Bromo-2-methylpropane and bromoethane in the presence of metallic sodium
5. 5.

   Which of the following statements correctly explains why diethyl ether has a significantly lower boiling point (34.6 °C) than its constitutional isomer 1-butanol (117.7 °C)?

   • A) Diethyl ether is a nonpolar molecule with zero net dipole moment, so it experiences only weak London dispersion forces.
   • B) Diethyl ether has a significantly lower molecular mass than 1-butanol, leading to much weaker dispersion forces.
   • C) Diethyl ether molecules engage in extensive intramolecular hydrogen bonding that prevents intermolecular attractions.
   • D) Diethyl ether lacks a hydrogen atom bonded directly to oxygen and cannot form intermolecular hydrogen bonds with itself, unlike 1-butanol.

Answers and step-by-step solutions appear after you finish the test.