eboard ver t Ser- ine Foods that taste sour often contain acids. For example, lemons contain citric acid and vinegar contains acetic acid. Many chemical reactions and biological processes are quite sensitive to acidity. The traditional "acid test of a solution involves dipping a colored piece of Litmus paper into the solution to be tested. If the paper changes color from blue to red, the solution is acidic. If there is no color change, the solution is tested with red litmus paper. If the red litmus paper changes to blue, the solution is basic (the opposite of acidic). In practice however, we seek to avoid "dipping" paper into our solutions. The prescribed method for testing acidity is to 1. a) stir the solution with a stirring rod, 2. b) touch the stirring rod to a piece of litmus paper and observe the resulting color. The fraction of a drop that clings to the stirring rod is sufficient to produce a color change. (Be conscious of contamination. Return stirring rods to the proper beakers immediately after use!) 1. Litmus Test of Common Household Chemicals Litmus Test Results a) ammonia caused b) vitamin C caused c) detergent caused d) vinegar caused e) 7 Up caused f) Drano caused g) Tea caused litmus to turn litmus to turn litmus to turn litmus to turn litmus to turn litmus to turn litmus to turn indicating that it is a indicating that it is a indicating that it is a indicating that it is a indicating that it is a indicating that it is a indicating that it is a U