Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

Louis Hammett developed a function relating their strength to thermodynamic activity coefficients. The pH of a solution is related to the negative log of their namesake equilibrium constant by the Henderson- Hasselbalch equation. Boron triflouride has an unpaired p orbital, which makes it the Lewis variety of these chemical substances because it readily accepts electrons. According to the Bronsted-Lowry definition, they donate protons. These produce hydronium in water according to the Arrhenius definition. For 10 points, name these chemicals which have a pH less than seven.
Science