Acid and base are terms used by chemists to categorize chemicals according to their pH. An acid is generally considered to be any material that gives up a hydrogen ion in solution, while a base is any material that creates a hydroxide ion in solution. Many of these acids and bases are familiar in everyday life. The vinegar we use in salad dressings gets its tart flavor from acetic acid, and one of the most common household drugs, aspirin, is a type of acid. Proteins, butter and oils, fruits and berries all contain a number of natural organic acids. Bases, which feel slippery when dissolved in water, are used to make soap and other household products. When people get heartburn, they might take baking soda or an antacid tablet, which are both mild bases. Countless industrial processes use acids and bases as reactants or...