This time we will go on a hunt. No, we are not hunting for birds or insects. Instead, we are hunting for acid. The word "acid" usually makes people think of dangerous chemicals, burning and corroding, but it describes an entire range of chemicals.
OK, so where are we going to look for acids? Not in your car, although there is acid in the car battery. Instead, we will look for acids in your refrigerator. The refrigerator! What would acid be doing in there? As we shall see, it is sitting there waiting for you to consume it.