To 1 mL of acetone in a small test tube, add 1 drop of the liquid or about 10 mg of a solid compound. Then add 1 drop of the Jones reagent and note the result within 2 sec. Run a control test on the acetone and compare the result.
Jones Reagent: A suspension of 25 g of chromic anhydride (CrO3) in 25 mL of concentrated sulfuric acid is poured slowly with stirring into 75 mL of water. The deep orange-red solution is cooled to room temperature before use. A good grade of acetone should be used. Some samples of acetone may become cloudy in appearance in 20 sec, but this does not interfere, providing the test solution becomes yellow. If the acetone gives a positive test, it should be purified by adding a small amount of potassium permanganate and distilling.
A positive test for primary or secondary alcohols consists in the production of an opaque suspension with a green to blue color. Tertiary alcohols give no visible reaction within 2 sec, the solution remaining orange in color. Disregard any changes after 2 sec.
Aldehydes are better characterized in other ways. The color usually develops in 5 - 15 seconds.
Enols may give a positive test.
Phenols give a dark colored solution which is not blue-green like a positive test.
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