# chromic acid test negative

or some limitations? Quick link too easy to remove after installation, is this a problem? Unknown alcohol sample. Does resorcinol give positive iodoform test? What can this chemical be? ... Amylose fives a postive iodine test and negative test with Feelings reagent. x.x. Where should small utility programs store their preferences? So I did lucas test as well but noticed later that it didn't help because my sample is not very soluble in water. Chromic acid may also refer to the molecular species, H2CrO4 of which the trioxide is the anhydride. Figure 6.37: a) Addition of orange chromic acid reagent to a solution of 2-butanol in acetone (before and after), b) Negative result and positive results for the chromic acid test. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. Still have questions? Can anyone help me solve this chemistry problem. I went to a Thanksgiving dinner with over 100 guests. MAINTENANCE WARNING: Possible downtime early morning Dec 2/4/9 UTC (8:30PM…, “Question closed” notifications experiment results and graduation. help needed for organic chem MC question? Moreover, if your "alcohol" is immiscible with water, that means it is one of the higher alcohols. It indeed smelled different than any other alcohols I have smelled. Add 2 mL of 3 M sodium hydroxide and then slowly add 3 mL of the iodine solution. Thanks for contributing an answer to Chemistry Stack Exchange! The disappearance of the red-orange color of chromic acid and the formation of a blue-green color of the Cr (III) ion indicates a positive test. I would recommend to repeat all the experiments one more time. It had a faint mint smell. Why bm uparrow gives extra white space while bm downarrow does not? Why is the concept of injective functions difficult for my students? Judging by the great amount of precipitate I got from the iodoform test, I'm thinking that maybe my sample is indeed a primary or secondary alcohol but it has something that won't react with the chromic acid. Can it be justified that an economic contraction of 11.3% is "the largest fall for more than 300 years"? OOP implementation of Rock Paper Scissors game logic in Java. You could have a tertiary alcohol that also contains a methyl ketone functionality. Lucas Test Mechanism. How to ingest and analyze benchmark results posted at MSE? Chromic Acid Test blue/green = positive. Stopper the test tube and shake vigorously. ...Show more. Why does chrome need access to Bluetooth? The reasons for such results may be: You had dirty test tube for ceric nitrate test, and it was really false positive. How to identify an unknown compound with spectroscopic data? • Phenols, aromatic amines, and aromatic RCHO’s (having hydroxyl or amino groups) give dark precipitates. 2) delta-Pinene. You added too much chromic acid, and had low amount of your "alcohol". • 1o & 2o ROH, aliphatic RCHO give + test w/in 5s. Join Yahoo Answers and get 100 points today. 3)1-Butanol. What is the cost of health care in the US? Reminds me of the time when my Russian co-worker took the flask off the rotavap, sniffed it and proclaimed ‘Smells like product’. Why does Slowswift find this remark ironic? It is a strong and corrosive oxidising agent. • Aromatic RCHO gives + test w/in 30-45s. The OH group belonging to the alcohol is protonated by the hydrochloric acid. Why does diethyl ether have the smallest dipole? What is the IUPAC name for ch3-ch2-c(double bond o)-ch3? Ceric ammonium nitrate will oxidize tertiary alcohols (because it oxidizes to an alkene rather than a carbonyl), whereas chromic acid cannot oxidize a tertiary alcohol, since that'd result in a "Texas carbon". The Chromic acid test works as shown below: A positive oxidation reaction is indicated by disappearance of the orange color of the reagent and the formation of a green or blue-green precipitate or emulsion. I have no clues of how to make sense into this. You could also try to identify it (if it's really an alcohol) by smell: those alcohols have pretty distinctive smells. site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. Please check your Tools->Board setting. MathJax reference. Note that if the unknown is not soluble in water, two layers may be present. Tertiary alcohols give a negative result with this test (Figure 6.56). Step 1. Iron Chloride Test purple or green = positive. 4) 2-Methyl-2-propanol. This kind of chromic acid may be used as a cleaning mixture for glass. You could have a methyl ketone, which gives negative chromic acid test and positive iodoform test. a negative test (left) and a positive test (right) You should know which alcohols above are primary, secondary, and tertiary and then you can answer it yourself.