Faculty of Pharmacy
Organic Chemistry Laboratory
APPLICATION OF DIFFERENT KINDS OF TEST TO CLASSIFY HYROXY- AND CARBONYL-CONTAINING COMPOUNDS Jane Catherine SP. Villanueva, Edenn Claudine C. Villaraza, Lorenz Oliver C. Villegas and Cristel Bernice T. Wee Group 10 2G-Medical Technology Organic Chemistry Laboratory ABSTRACT
Hydroxyl group refers to a functional group containing OH- when it is a substituent in an organic compound. It is also known as the characteristic functional group of alcohols and phenols. On the other hand, carbonyl group refers to a divalent chemical unit consisting of a carbon and an oxygen atom connected by a double bond. It is known as the characteristic functional group of aldehydes and ketones instead. In this experiment, hydroxyl- or carbonyl- containing samples were given to the group for examination. The samples were analyzed through different tests namely the involvement of the solubility of alcohols in water, the Lucas Test, the Chromic Acid Test or also known as Jones Oxidation, the 2,4-Dinitrophenylhydrazone (2,4-DNP) Test, the Fehling’s Test, the Tollens’ Silver Mirror Test, and the Iodoform Test. The solubility of alcohols in water test showed that the sample, benzyl alcohol was immiscible while ethanol was the most miscible from all the other compounds used. While in Lucas Test which was used to differentiated the primary, secondary, and tertiary alcohols had turned tert-butyl alcohol into a cloudy solution afterwards. In Chromic Acid Test which was a test for oxidizable compounds or any compounds that possess reducing property would yield to a blue green solution if it reacted positively. This was seen in all the sample used in this test except for acetone. Whereas Dinitrophenylhydrazone (2,4-DNP) Test was preformed to test for aldehydes and ketones which would result to a yellow orange precipitate if it was positively reacted. All the compounds subjected to this test namely n-butyraldehyde, benzaldehyde and acetone gave a positive result. Fehling’s Test and Tollens’ Silver Mirror Test were used to tests for aldehydes. In Fehling Test, both the n-butyraldehyde and benzaldehyde gave a positive result which was a brick red precipitate but acetone gave a negative result which was only a blue solution. While the Tollens’ Silver Mirror Test had shown that both n-butyraldehyde and benzaldehyde gave a positive result which was a silver mirror and then again acetone gave a negative result which was the absence of a silver mirror. Lastly Iodoform test was performed and was known as a test for methyl carbinol and methyl carbonyl groups. Both acetone and isopropyl alcohol resulted to a positive outcome in this test which was formation of yellow precipitate but n-butyraldehyde on the other hand yield to a negative result which was a yellow solution containing black precipitate.
In organic chemistry, classification of test was tests that categorize a substance into one of several classes. They were used to detect functional groups and other structural features.
Alcohol were derivatives of hydrocarbons in which one or more of the hydrogen atoms have been replaced by a hydroxyl (-OH) functional group. Hydrocarbons are compounds which contain hydrogen (H) and carbon (C) only. The hydroxyl group imparts particular properties to the radical to which it is attached. 
Alcohols are classified into three categories: primary (1°), secondary (2°) and tertiary (3°). This classification is based on the number of carbon-containing groups (R for an alkyl or an aromatic group) attached to the carbon bearing the hydroxyl group. If the carbon bearing the OH has one R group, the molecule is a primary alcohol. If two R groups are attached, it is then a secondary alcohol. If three R groups are attached, then the alcohol is tertiary
Figure 2. Three alcohol groups
There are other molecules...