Simple distillation is used when separating a pure liquid from impurities, not mixtures. It works best when the difference in boiling points is greater than 50 degrees Celsius.
Related terms
Impurity: A substance in another substance (especially a small amount) that is not wanted or is considered to be harmful.
Purification: The process of removing unwanted substances from something.
Boiling Point Difference: The difference in temperature at which two substances change from liquid to gas.