SolutionsPhysical and Bond Properties
1. Isomers
Ethanol and dimethyl ether have the same formula, C2H6O. Why does ethanol boil at 78 °C and the ether at −25 °C?
Ethanol forms hydrogen bonds between its molecules; the ether cannot, because it has no hydrogen bonded to oxygen.
2. Solubility
Diethyl ether is somewhat soluble in water (about 69 g/L) although it does not form hydrogen bonds with itself. Why?
Because the lone pairs of its oxygen can accept hydrogen bonds from water.
3. Epoxide strain
Why is ethylene oxide much more reactive than tetrahydrofuran?
Because of the strain of its three-membered ring: the internal angles of about 60° are far from the 109.5° of sp3 atoms, and ring opening releases that strain.