Application:  Like many other color additives, the primary use of Blue No. 1 is to correct or enhance natural coloring or to give colorless compounds a vivid hue. Brilliant blue FCF dye within beverages items—such as soda—can be used in the blue bottle experiment. In such foods, both the dye and reducing agents are incorporated in the same solution. When the solution is blue, oxygen is present. On the addition of NaOH, a reaction occurs that removes the oxygen, turning the solution clear. The dye turns back to blue once it is reoxidized by swirling the solution, incorporating oxygen from the air as an oxidizing agent