Today in lab we titrated a known amount of an acid called potassium hydrogen phthalate, in order to determine the precise concentration of a base called sodium hydroxide. Then we used the sodium hydroxide to titrate a known amount of vinegar to determine the concentration of acetic acid in the vinegar.
It is a nice, two-step lab that reinforces the student's grasp of solution chemistry, acid-base equilibria, stoichiometry, and a few other concepts. The way this course is arranged, their knowledge builds as we proceed from chapter to chapter in the textbook. In other words, they really aren't supposed to forget anything during the whole semester. Students hate that, until they move on to the next class. Then they sometimes come back and thank me. Not always, but sometimes...