If a red color develops or if the solution becomes colorless, the dioxane must be purified. If the mixture remains yellow or is only a light orange-yellow, it may be used to test water insoluble compounds. Divide the 6 mL of the solution in half, reserving 3 mL for observation as a control. To the other 3 mL of the dioxane containing reagent, add 4 or 5 drops of a liquid unknown or 0.1-0.2 g of a solid. Mix thoroughly and make the same observations as above.
Phenols give a brown color or precipitate as a positive test.