Specify whether a simple distillation or a fractional distillation would be more suitable for each of the following purifications, and briefly justify your choice.
Preparing drinking water from sea water.
Separating benzene, bp 80 deg C, from toluene, bp 111 deg C.
Obtaining gasoline from crude oil.
Removing diethyl ether, bp 35 deg C, from p-dichlorobenzene (s), mp 174-175 deg C.