1. Caffeine 2. Acetaminophen 3.Aspirin 4. Ibuprofen The standard compounds start with caffeine being the most polar compound due to it containing carbonyl groups that keep the compound in place. Pills that help students stay awake to take exams such as no-doz and stay awake contain caffeine. Tea and coffee also can stimulate the nervous system. Caffeine is the most polar due to amine groups and hydrogen bonds. Acetaminophen is somewhat soluble and is a common compound used in Tylenol. This is due to the charge spreading throughout the molecule. Ibuprofen is commonly used in Advil. Aspirin is the most water soluble substance and is commonly used as a pain reliever.