Today we are extracting citric acid from some large large lemons. Citric acid is quite a useful molecule in general, but I don't have any particular uses for it. It is mostly used as a pH buffering agent in chemistry and isn't use in direct synthesis. A buffering solution is a solution that resists pH change. It is useful in synthesis when you need to keep the pH relatively constant during a reaction. In my Cadaverine video, I used citric acid to make a pH buffer solution: https://youtu.be/C5